First Study to Demonstrate Ergogenic Effects of Metformin - 14% Increased Time to Exhaustion in Standardized Supra-Maximal Cycling Test With 500mg of Ordinary Metformin

With the publication of Learsi's latest paper the list of things metformin can do for you has just gotten been expanded with another item: Doping!

You will probably remember my article about the potential, but unproven ergogenic effects of AMPK mimetics (read it). Well, as it is often the case, a new study is released only days after you've published a review of the existing literature. Oftentimes that's not really relevant, but in the case of the latest study from the Federal University of Alagoas this may be different. After all, we are dealing with a human study in  ten healthy, physically active, but non-athletic subjects with a mean (±SD) maximal oxygen uptake (VO2max) o 38.6 ± 4.5 mL/kg per min who performed (i) an incremental test; (ii) six submaximal constant workload tests at 40%-90% V O2max; and (iii) two supramaximal tests (110% V O2max).

All tests were performed twice once with a placebo supplement and once with 500mg of metformin. Both, the placebo and the metformin supplement were ingested 60 minutes before the supramaximal test, in order to investigate the hypothesis that metformin would increase anaerobic capacity and performance during high-intensity, short-duration exercise.

Like antioxidants metformin could blunt the hormetic response & long-term(!) adaptation

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Antiox. & Health Benefits Don't Correlate

The authors, Learsi et al. (2015), based this hypothesis on the fact that metformin inhibits aerobic pathway energy production and so the glycolytic energy system could be overloaded during ATP production for muscle contraction.

Figure 1: Overview of the study design. The active / placebo treatment, i.e. 500mg of metformin or an identically looking placebo were administered 60 min before the supramaximal tests. The whole procedure was repeated twice, with at least 72h between the first and the second testing session (Learsi. 2015).

The aim was thus to to determine the effects of metformin on anaerobic capacity and to elucidate whether metformin has any ergogenic effect in intense, short-duration exercise in healthy, physically active men.

Is this really the first study? Yes, it is the first to prove metformin's ergogenic effects in humans. It's yet not the first human study to test the ergogenic effects of metformin. 2008 Johnson et al. made the mistake to assume that taking metformin would affect the VO2max, or ventilatory threshold. Just like Gudat et al. before them, Johnson et al. simply missed the most straight forward practical measure of exercise performance, i.e. total time to exhaustion, while focusing on things like VO2 (Johnson et al. 2008) or lactate (Gudat et al. 1997) which are nice to explain increases in performance, but - if we are honest - still irrelevant, when all that really counts is how fast you run, how long you cycle or how hard you hit.

While many of the variables they assessed didn't change, the already hinted at 14% increase in maximal endurance (see headline) is something that may make the difference between winning an Olympic medal and placing fourth or worse.

Figure 2: Changes in time to exhaustion and EPOC, both stat. significantly w/ metformin (Learsi. 2015).

What is also noteworthy is that the subjects excess post-exercise energy consumption, which was measured for (unfortunately) only 10 min, increased significantly, as well (see Figure 2, right). In contrast to what some bro-scientists may tell you that does not necessarily equal increased fat loss, but it's still interesting, because it may suggest that metformin improved the subjects' performance by increasing the supply of energy via the anaerobic alactic system, i.e. by boosting the efficacy of non-glucose- and thus non-lactic-acid-dependent energy pathways - in short: fat oxidation.

Alpha Lipoic Acid, GABA, Taurine, Green Tea, Gooseberry & Fenugreek. Plus: Metformin the No.1 Drug? Supplements to Improve and Restore Insulin Sensitivity - Read the First Installment of This Series | read more

Bottom line: This is the first human study to confirm that the AMPK-booster and frequently prescribed diabetes drug can trigger statistically and practically relevant increases in endurance performance during a supra-maximal VO2 max test. If we assume that a similar performance increase occurs in trained athletes, the Learsi study makes taking a bunch of grandma's metformin pills before the next race quite attractive. For the WADA, however, it means that they will have to watch and test for yet another commonly prescribed and readily available medication. And last but not least, for the "wonder-drug" metformin, it is yet another area of application: athletic performance enhancement or as we usually call it "doping" | Comment on Facebook!

References:

• Gudat, U., G. Convent, and L. Heinemann. "Metformin and exercise: no additive effect on blood lactate levels in healthy volunteers." Diabetic medicine 14.2 (1997): 138-142.
• Johnson, S. T., et al. "Acute effect of metformin on exercise capacity in active males." Diabetes, Obesity and Metabolism 10.9 (2008): 747-754.
• Learsi, et al. "Metformin improves performance in high-intensity exercise, but not anaerobic capacity." in healthy male subjects." Clin Exp Pharmacol Physiol. 2015 Aug 7. doi: 10.1111/1440-1681.12474. [Epub ahead of print]

ALA, Berberine, Metformin, Resveratrol, AICAR & Co - Are AMPK Mimetics & Activators Good or Bad for Athletes?

Unless you're planning to just sit, instead of cycle on your spinning bike, it is by no means sure if your performance well benefit or maybe even suffer from the use of AMPK mimetics and activators.

Recently someone asked me on Facebook, whether AMPK activators like Lipoic acid (ALA), Berberine, Metformin, AICAR & Co wouldn't make excellent performance boosters. I pondered that question for some time and said: "If you are about to compete in a highly glycolytic sport, the opposite is probably the case."

There's little question that supplements like lipoic acid are useful if you are an overweight type II diabetic. But let's be honest: How many of you fall into this category? As healthy, active individuals or even athletes, on the other hand, you should be aware that the ability of these agents to increase the glucose uptake and block the glyconeogenic pathways in the liver may easily make you run out of fuel during anaerobic activities like lifting or sprinting.

Learn more about hormesis and how antioxidants can also impair your gains

Is Vitamin E Good for the Sedentary Slob, Only?

Even Ice-Baths Impair the Adapt. Process

Vit C+E Impair Muscle Gains in Older Men

C+E Useless or Detrimental for Healthy People

Vitamin C and Glucose Management?

Antiox. & Health Benefits Don't Correlate

This does not negate the fact that AMPK activators, by their ability to increase the use of free fatty acids as a substrate, may be of interest to endurance runners or athletes competing in other sports, where the lion's share of the energy they use during their workouts and competitions are carboxylic acids with a long aliphatic tail (chain), i.e. fatty acids.

Against that backround it is hardly surprising that the few pertinent studies that exist are - at least in parts - contradictory. Shortly before the last Olympic Games in Beijing, for example, a study was published that showed that the research chemical and AMPK activator AICAR (5-amino-1-b-D-ribofuranosyl-imidazole-4-carboxamide) increased the running capacity of mice without any training. But let's be honest: Do you think athletes would be looking for agents that work without training... well, obviously they would, but AICAR - as potent as it may be - will never replace the blood, sweat and tears athletes have to invest to be successful. That's for sure.

Which AMPK activators are actually prohibited by the WADA? The WADA list of prohibited substances lists only "AMP-activated protein kinase (AMPK), e.g. AICAR; and Peroxisome Proliferator Activated Receptor δ (PPARδ) agonists e.g. GW 1516" which is pretty unspecific and leaves me questioning whether other natural AMPK activators like ALA, berberine, chlorogenic acid or the most widely used one, i.e. metformin, would be illegal, too.

Nevertheless, the observation Narkar et al. (2008) made was enough for the World Anti-Doping Agency (WADA) to include certain AMPK activators in the list of forbidden drugs - for all, not just endurance sports, obviously.

Table 1: Adenosine monophosphate-activated kinase activators and their impact on exercise capacity (Niederberger. 2015)

Actual experimental evidence of performance enhancing effects exists for several natural and synthetic AMPK mimetics and activators (see Table 1). If you look closely, however, you will notice that all those "enhacnements" and "increases" have been in rodent models and/or non-athletes.

What does the latest review say? As usual, the special needs of Olympic-lifters, bodybuilders, sprinters and all other athletes who are competing in anaerobic sports are ignored by the authors of the latest and - as far as I know - first review of the impact of the activation of AMPK on sports performance.

It's the increase in the total time and endurance as well as VO2 in a injection only (no training) rodent study observed by Narkar et al. in 2008 that is behind all the hype around AICAR as a "potent doping agent". I wonder if the athlete who use is even know that the mice in the study didn't even train. Whether the effect is additive is thus highly questionable.

In spite of their unfortunate ignorance of sports-specific differences, Niederberger et al. (2015) produce a neat overview of the available research on AMP mimetics like AICAR, pharmacological drugs like metformin, salycilic acid, thiazolidinediones, Phenobarbital and Telmisartan, and natural AMPK activators like green tea, capsaicin, resvertrol and co. Of these, none has been tested in athletes, though, even the applauded AICAR helps only in theory (!). Unlike Niederberger's review suggests, the performance enhancing effects in studies like (Hayashi. 1998; Cuthbertson. 2007; Narkar. 2008) were after all observed in the absence of baseline training and are thus not representative of what would happen in athletes who won't be dumb enough to believe that they don't even have to train if they are abusing AICAR.

The lack of relevant evidence for performance benefits in athletes that would be induced by AMPK mimetics, as well as the existing evidence that AMPK promoters like resveratrol, which don't target AMPK primarily, but must be thought of as potent antioxidants instead, entail the risk of anti-hormetic effects (e.g. the attenuation of the positive effects of endurance exercise on inflammatory and oxidative stress markers in aged men in response to 250mg resveratrol day in Olesen et al.'s 2014 study) put a huge "?" behind the actual usefulness of AMPK mimetics and promoters as athletic performance enhancers..

In the absence of experimental evidence from both rodent and human studies that involve AMPK activators and anaerobic exercise, we have to use our brains to find out whether sprinters, bodybuilders, or weight lifters and athletes competing in team sports that have both an aerobic and an anaerobic component would benefit as well. In this case the extensive research on alpha lipoic acid (ALA) can help us, but we should not forget that the effects may differ from one agent to the other.

Due to the previously mentioned potentially negative effect on blood glucose in insulin sensitive individuals that is mediated primarily by increases in whole body glucose oxidation, increased glycolysis (wasting of the glycogen reserves| Barnes. 2004) and a reduced ability to produce new glucose "on demand" (via gluconeogenesis, which is AMPKs main of glucose control according to Zhang et al. 2009), athletes competing in anaerobic sports may in fact run the risk of running low on blood sugar and thus compromising their performance and/or being even more reliant on sugary high carbohydrate beverage.

In insulin sensitive muscle cells ALA reduces the rate of glycogen synthesis (Dicter. 2002). This should remind you of this simple truth: What's good for your obese neighbor, ain't necessarily good for you. Plus: ALA ain't the only supplement with different, often opposite effects in lean vs. obese.

What's good for the obese is rarely good for athletes: The reduced protein synthesis (Figure 1) is only one of several undesirable side effects of high doses of ALA. One that people usually won't even believe exists is an impairment of glycogen synthesis in insulin sensitive skeletal muscle. While ALA is famous for partly restoring the whole body (including body fat) glucose uptake in insulin resistant individuals, studies like the one by Dicter et al. (2002) indicate that it will reduce the insulin-induced glycogen synthesis if the muscle in question is not insulin resistant, but sensitive. That's an effect that may occur only at higher dosages of ALA (and other potent AMPK activators), but still one that no athlete can ignore.

If you don't care about blood glucose, you may be intrigued to hear that AMPK will not act on your glucose metabolism, alone. Increasing levels of AMPK will also suppress skeletal muscle protein synthesis (Figure 1), which is a side effect that's probably even worse than the remote risk of hypoglycemia, specifically in athletes competing in anaerobic sports.

Figure 1: Changes in p-AMPK and nutrient-induced protein synthesis in myotubes from the EDL muscle (Saha. 2010).

Now, some of you may argue that I personally wrote in an older article in the Intermittent Fasting Series that the rise in AMPK due to exercise would not be a problem.

If you'd read that article carefully, though, you'd also know that this is because exercise triggers the release of a specific form of AMPK that's different from the one that's released during fasting and in response to regular AMPK activators. It is thus not unlikely that high(er) intakes of ALA as they would probably be abused by athletes, who (falsely) believe they'd benefit from it, can impair the protein synthesis to a similar extent as it was observed by Saha et al. in their 2010 study in rodent EDL muscles.

Furthermore animal studies show that chronic administration of albeit very high doses of ALA, equivalent to ~5g/day for a human being, will actually trigger significant reductions in lean mass (Shen. 2005) - something almost every athlete who's competing in anaerobic sports will want to avoid.

The answer to the question in the headline is - as so often: "It depends!" If you are an endurance athlete, the acute, yet not the chronic consumption of the AMPK mimetics (=acts just like) like AICAR and maybe some of the less potent AMPK activators could improve your endurance. Without studies where the rodents (or even better men and women) are actually trained, even this assumption is speculative.

Figure 2: While the last word has not been spoken, yet the impaired adaptive response to stressors in older subjects supplementing w/ 250mg/day resveratrol Olsen et al. observed in 2014 is further evidence that the chronic consumption of potent antioxidants (which happen to be AMPK promoters in this and other cases like ALA) must not be recommended unconditionally for athletes based on the available evidence.

If, on the other hand, you're competing in sports where anaerobic performance, i.e. power, speed and other parameters that will critically depend on the availability of glucose, you will probably see no beneficial and, in the worst case, detrimental effects.

These detrimental effects could also occur in response to the chronic ingestion of AMPK promoters like lipoic acid due to their potentially negative effect on protein synthesis and glycogen repletion, as well as in response to the chronic use of potent anti-oxidants for which evidence exists that they impair the hormetic response to exercise and may thus be detrimental for athletes competing in both anaerobic and aerobic sports.

If you take small amounts of berberine, ALA, resveratrol, or other agents that have been shown to exert their health benefits via AMPK, though, it is very unlikely that the previously discussed unwanted side effects surface (don't expect direct ergogenic effects, though). Moderation is - as so often - the key to perfect happiness | Comment on FB!

References:

• Barnes, Brian R., et al. "The 5′-AMP-activated protein kinase γ3 isoform has a key role in carbohydrate and lipid metabolism in glycolytic skeletal muscle." Journal of Biological Chemistry 279.37 (2004): 38441-38447.
• Cuthbertson, Daniel J., et al. "5-Aminoimidazole-4-carboxamide 1-β-D-ribofuranoside acutely stimulates skeletal muscle 2-deoxyglucose uptake in healthy men." Diabetes 56.8 (2007): 2078-2084.
• Hayashi, Tatsuya, et al. "Evidence for 5′ AMP-activated protein kinase mediation of the effect of muscle contraction on glucose transport." Diabetes 47.8 (1998): 1369-1373.
• Narkar, Vihang A., et al. "AMPK and PPARδ agonists are exercise mimetics." Cell 134.3 (2008): 405-415.
• Niederberger, Ellen, et al. "Activation of AMPK and its Impact on Exercise Capacity." Sports Medicine (2015): 1-13.
• Olesen, Jesper, et al. "Exercise training, but not resveratrol, improves metabolic and inflammatory status in skeletal muscle of aged men." The Journal of physiology 592.8 (2014): 1873-1886.
• Saha, Asish K., et al. "Downregulation of AMPK accompanies leucine-and glucose-induced increases in protein synthesis and insulin resistance in rat skeletal muscle." Diabetes 59.10 (2010): 2426-2434.
• Shen, Q. W., et al. "Effect of dietary α-lipoic acid on growth, body composition, muscle pH, and AMP-activated protein kinase phosphorylation in mice." Journal of animal science 83.11 (2005): 2611-2617.
• Zhang, Bei B., Gaochao Zhou, and Cai Li. "AMPK: an emerging drug target for diabetes and the metabolic syndrome." Cell metabolism 9.5 (2009): 407-416.

Caffeine & Cholorogenic Acid - Anti-Obesity Agents from Your Coffee Mug? Human Study Reveals Cortisol Lowering Effects, Mouse Study Confirms Anti-Obesity Effects

Ever since the Vinson study showed that green coffee bean extracts can help overweight women lose weight, green coffee is sexier than roasted one.

Only weeks after Vinson et al. were able to show that "Green Coffee Bean Extract Helps Pre-Obese Men and Women Shed 16lbs in 22 Weeks" (read more), green coffee bean supplements began to swamp the market - a great financial success for the supplement producers, and that despite the fact that follow-up studies that would confirm the amazing effects Vinson et al. report are still lacking. Two recent studies, one from the Queen Margaret University in the UK (Revuelta-Iniesta. 2014), the other from the  Jiangxi Agricultural University in the People's Republic of China (Zheng. 2014) could now shed a little more light on the weight loss effects of green coffee beans and the combination of caffeine and cholorgenic acid (CGA), the allegedly most important active ingredient in unroasted, green coffee beans.

There is evidence of beneficial effects of GCA on your gut microbiome (Jaquet. 2009)

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In their 24-week rodent study, Zhang et al. (2014) tried to elucidate the mechanism by which CGA and caffeine regulate lipid metabolism. To this ends, they randomized their forty hairy subjects to diets containing no CGA or caffeine, CGA, caffeine, or CGA + caffeine.

Figure 1: Rel. (vs. control) body weight changes and liver and intraperitoneal adipose tissue weight (Zhang. 2014)

Over the course of the 24-weeks study, the scientists recorded body weight, intraperitoneal adipose tissue (IPAT) weight, and serum biochemical parameters of the rodents, tracked the the activities and mRNA and protein expression of lipid metabolism-related enzymes and analyzed the effects of caffeine, CGA and the combination of the two. What they found was...

1. 

   Figure 2: Effects of chlorogenic acid (CGA) and caffeine on the hepatic protein
   expression levels of AMP-activated protein kinase (AMPK), adipose TAG
   lipase (ATGL) and fatty acid synthase (FAS; Zhang. 2014)

   decreases in the body weight and IPAT weight of mice fed the CGA + caffeine diet,
2. significant decreases in the serum and hepatic concentrations of total cholesterol, TAG and leptin of mice fed the CGA + caffeine diet,
3. increases of the activity of carnitine acyltransferase (CAT) and acyl-CoA oxidase (ACO), 
4. decreased levels of fatty acid synthase (FAS) and the respective mRNA levels
5. significantly upregulated mRNA expression levels of AMP-activated protein kinase (AMPK), CAT and ACO
6. pronounced reductions of PPARg2

If we group these findings as follows 3 + 5 and 4+6, we could say that they triggered 1 + 2 by (a) increasing the oxidation of fatty acids (3+5) and (b) decreasing the synthesis and storage of fatty acids (4+6) - an observation that could certainly explain the benefits Vinson et al. observed in their human study which has been retracted in October 2014, though. On the other hand, the amount of CGA and caffeine in the rodent diets (0.2 % CGA + 0.03 % caffeine) was quite significant and previous rodent studies on other allegedly promising fat burners were not replicable in human beings either (example: CLA). Against that background it's good to have study #2 by R. Revuelta-Iniesta and E. A. S. Al-Dujaili, who investigated the effects of green coffee (GC), rich in chlorogenic acid, and black coffee (BC) on cardiovascular markers.

New human data with surprising results

The researchers designed a randomised pilot crossover study with healthy subjects who consumed both coffees for 2 weeks.

• The green coffee (GC) used in this project was Ethiopian Harrar 4 (100% Arabica) and the black coffee (BC) was Sainsbury’s Original Blend Cafetitère Coffee.
• The BC was  a blend of Brazilian, Colombian, Mexican, Nicaraguan, Peruvian, and Rwandan beans.

The study participants were asked to have 40 g of GC and BC per day distributed throughout the day into four cups of coffee. Thus, the scientists tried to ensure that high plasma coffee antioxidant concentrations were maintained over a period of time, "allowing effects to take place and the body to develop tolerance to caffeine, which can take 2-3 days." (Revuelta-Iniesta. 2014).

Table 1: Concentration of total polyphenols and antioxidant capacity determined in GC and BC as compared by the three methods of  coffee preparation (Revuelta-Iniesta. 2014).

The GC beans were grounded to powder using an electric coffee grinder. Instructions on how to make the coffee were provided and the Italian cafetière, the French cafetière, or the filter coffee machine was used to prepare the coffee drink.

The researchers measured anthropometry, blood pressure, and arterial elasticity after each intervention and collected urine samples to monitor antioxidant capacity. The free cortisol and cortisone levels you see in Table 2 were obtained from urine and analysed by specific ELISA methods.

Table 2: Comparison of results obtained (mean±SEM) after 14 days of green coffee vs. black coffee intervention (2-week cross over study); F: cortisol; E: cortisone; orange = almost bordeline significant; green = statist. significant inter-group difference (Revuelta-Iniesta. 2014).

In view of the short duration of the study (remember 2 weeks on each coffee), it's not really surprising that we didn't see changes in any of the anthropometric measures. On the other hand, the mere fact that the cortisol/cortisone ratio (indicating 11beta-HSD1 activity) was reduced after GC (from 3.5 +/- 1.9 to 1.7 +/- 1.04, P = 0.002) does not suggest that you will see beneficial effects on body composition in the absence of significant reductions in energy intake. A reduction in glucocorticoid activity can in fact hamper not accelerate weight loss (learn more) and the researchers hypothesis that "GC can play a role in reducing cardiovascular risk factors" (Revuelta-Iniesta. 2014) is a possible, but unconfirmed hypothesis.

Yes, agents like glycerric acid from licorice increase cortisol levels. Contrary to common believe this will yet not trash your testosterone levels and/or induce weight loss - quite the contrary | learn more

Bottom line: While the rodent study by Zhang et al. appears to support the accuracy of the data Vinson et al. published two years ago, you as a SuppVersity reader should be aware of the fact that the reduction in cortisol / cortisone activity Revuelta-Iniesta and Al-Dujaili observed in their subjects is not necessarily going to facilitate weight loss. As discussed in the corresponding Science Round Up, a normal circadian cortisol rhythm with both spikes and troughs is a prerequisite of optimal fat loss, so that it's suppression by green coffee beans or other means is beneficial only for those of us who suffer from chronically elevated cortisol levels.

Overall, we are thus left with a single study the whole "green coffee bean for weight loss"-hype is based on. Well, who cares. For the majority of best-selling supplements we don't even have that ;-)

References:

• Jaquet, Muriel, et al. "Impact of coffee consumption on the gut microbiota: a human volunteer study." International journal of food microbiology 130.2 (2009): 117-121.
• Revuelta-Iniesta, R., and E. A. S. Al-Dujaili. "Consumption of Green Coffee Reduces Blood Pressure and Body Composition by Influencing 11β-HSD1 Enzyme Activity in Healthy Individuals: A Pilot Crossover Study Using Green and Black Coffee." BioMed Research International 2014 (2014).
• Vinson, Joe A., Bryan R. Burnham, and Mysore V. Nagendran. "Randomized, double-blind, placebo-controlled, linear dose, crossover study to evaluate the efficacy and safety of a green coffee bean extract in overweight subjects." Diabetes, metabolic syndrome and obesity: targets and therapy 5 (2012): 21.
• Zheng, et al. "Chlorogenic acid and caffeine in combination inhibit fat accumulation by regulating hepatic lipid metabolism-related enzymes in mice." British Journal of Nutrition (2014). Ahead of Print.

Maintain & Increase Your Insulin Sensitivity - Wrap-Up: Overview + 3 Stacks. Plus: AMPK & PPAR-γ Revisited

It's not about exercise or nutrition, it's about both of them. And as long as it is not about the former it should not be about supplements either.

It's Sunday and finally time for the wrap up of the "Maintain & Increase Your Insulin Sensitivity" Series (read all previous installments). It took me quite some time to get through all the compounds on my and your list and the outcome is far from being a "complete" list of all the agents that can have beneficial effects on your insulin sensitivity. Still, if there is at least one agent, one fact or one take home message for each of the 6 previous articles of which you would say: "Ok, I guess that was worth wasting some of my valuable time on", I would be happy.

For myself it was by the way yet another occasion to learn more  about many of the agents, I reviewed in this series.

And if you listened to the SuppVersity Science Round-Up on Thursday, you will probably remember that I said that I was at least a cautiously excited about the potential of berberine... but I am wasting your time here. Let's start with the wrap up.

Lifestyle changes are more powerful than supplements: So don't forget that it's imperative to realize the lifestyle changes described in the first installment of this series. Otherwise the best you can hope to achieve with supplements (and drugs) is to slow the progression from insulin resistance to full-blown diabetes.

Before we take a look at the three stacks I have compiled, I do just briefly want to get you up to speed as far as the major underlying mechanisms of the supplements are concerned:

• AMPK: Some people in the medical establishment think of it as the good counter-part to mTOR. The fairy that will put an end to the pro-carcinogenic reign of the evil mTOR-witch, so to say. Others, who are mostly part of the "muscle head" community, think of AMPK as their fiercest enemy and mTOR as their brother in crime... It goes without saying that neither of these views is accurate. AMPK and mTOR are not even necessarily antagonistic - at least not for people like you - people who work out regularly. The mTOR expression after a workout does after all occur in the presence of increased an expression of AMPK. What else could you possibly ask for, if you want to "recomp" (i.e. lose fat and gain muscle to improve your physical appearance)?
  
  

  

  Few people know that there are two different iso-forms of AMPK. The alpha-2 isoform is the one that's expressed during a workout and it works hand in hand with mTOR and not against it (learn more)

  What may at first look like a paradox is actually easily explained if we don't look at the characteristic downstream effects of mTOR and AMPK, but rather at the circumstances in which they are activated. Outside of the previously mentioned exercise context those are in fact antagonist. With mTOR being triggered by the abundance of nutrients - specifically protein, and even more specifically leucine - you would not expect to see increases of AMPK at the same time. The latter is after all, expressed, when a cell senses a lack of nutrients in form of an increase in ADP (~used ATP) and a decrease in ATP levels. The reaction, i.e. an increased expression of AMPK will then have downstream effects on the uptake of glucose and the oxidation of fatty acids, both of which contribute to a restoration of normal ATP levels in the cell.
  
  Both AMPK and mTOR act highly localized. The exercise induced glucose uptake is thus muscle-specific - that should be obvious, since exercise will raise the ADP levels only in the muscle. Supplemental agents that mimic this effect, on the other hand, act systemically. Agents like alpha lipoic acid will therefore increase glucose uptake in both muscle and adipose tissue (Moini. 2002). After a workout and at other time points, where the glucose uptake is already high and, more importantly, muscle specific, it is thus not necessarily the best idea to try to "escalate" the effects by using a class of supplements that is often mislabeled as "insulin mimetics". 
• A note on the PPAR-effects of CLA, fish oil, TTA & co: I guess as a well-read SuppVersity reader you will know that CLA is a supplemental non-starter. In human studies the outstanding results from rodent trials have never been successfully replicated. This could be - at least in parts - a result of the dosage and the ratio of t10c12 CLA to it's c9t11 counterpart, which has the exact opposite effects on the PPAR-gamma receptor (Toomey. 2005).
  

  

  Some of you will probably also remember my articles about the pertinent effects of TTA and fish oil in the. Of those only the latter has a significant PPAR-gamma activity. TTA, on the other hand is predominantly a PPAR-delta and -alpha agonist and thus more a "true fat burner" than a general "fat handler", which is probably the best way to describe fish oil (learn more).
  PPAR-gamma: If you listened to the Science Round-Up last Thursday you will have heard me say that blocking PPAR-gamma will inhibit the storage of energy in the adipose tissue. That's true, but by no means as beneficial as you may be thinking. It is, for example, pretty likely that the CLA induced PPAR-gamma blockade is also responsible for the increased propensity to develop non-alcoholic fatty liver disease in CLA fed rodents.
  
  The results Fedor et al. present in a 2012 paper, show that these effects can be ameliorated if the PPAR-gamma suppressor (i.e. trans-10, cis-12-conjugated linoleic acid) is combined with a supplement that exerts the opposite effects in the liver - a supplement you all know pretty well: DHA, as in "fish oil". It is, just like many of the "older" diabetes drugs, an (allegedly less) potent PPAR-G agonist (=activator; cf. Neschen. 2006).
  
  Whether the blockade of PPAR-gamma is a good or a bad thing does thus obviously depend on the scenario we are talking about. For the lean individual, who is working out regularly and wants to defend his leanness in the absence of (un-)wanted eating orgies and "mass building regimen" it is probably a good thing. He or she will not have an energetic surplus that could end up clogging up the liver. And while the same goes for the average obese individual who has finally gotten his act together, PPAR-gamma inhibitors would seem clearly counter-indicated for sedentary individuals on the high calorie, high sugar, high fat diet so many people consider "normal", these days.
  
  As paradox as it may seem, the anti-diabetic effects of PPAR-gamma activating thiazolidinediones (TZDs) which are still used to "treat" (I should rather write "manage") diabetes mellitus and other diseases that feature insulin resistance will thus come at the expense of increased body fat storage. The latter can be pretty pronounced,as the data from pre-diabetic individuals Bray et al. published only recently goes to show you (figure 1).
  
  Despite their anti-inflammatory effects and their (limited) use in highly inflamed type II diabetics you will therefore not find any of the herbal PPAR-gamma agonists like pomegranate, pumpkin, mellisa officinalis, morus alba, artemisia capillaris, bitter melon, guggul, banaba or mulberry (cf. Huang. 2009) in the stacks below. And that despite the fact that they have anti-inflammatory activities.

Ok, I guess you are either fed up of theoretical details by now, or were so before and just scrolled down to the "stacks" in the first place.

There is a reason there is no "athlete's stack" here: Since I know you will be asking, I thought I will say it right away. The reason that there is no "athlete's stack" in the list is that athletes are either "normal-weight insulin resistant" or they are insulin sensitive and don't need any supplements on top of the lifestyle changes from episode I. You got your workouts, folks: There is no better muscle specific insulin sensitizer out there! If you are looking for agents to stay lean try berberine, it's anti-ppar-gamma effects may help and if you want more, stack it with taurine, of which you should by now know that its benefits go well beyond "glucose sensitizing" / You don't? Well, then take a look at the previous articles about taurine.

I guess I will not make you wait any longer, then... I have come up with three scenarios, the "insulin resistant obese / overweight individual", "the normal-weight insulin resistant individual" and the "cheater" (explanations follow below the stacks):

• 

  Table 1: List of the most important supplements discussed in the series; more details on each of them, as well as on those I did not include in this overview can be found in the individual installments.

  The insulin resistant obese / overweight individual will have to target weight and fat loss and increases in insulin resistance; a stack that could facilitate all three would contain.
• Metformin - 3x 300-500mg (not lipoic acid, this is why)
• Berberine - 3x 200-400mg
• Fucoxanthin - 3x 5mg
• Taurine - 3x 2-3g
• Chromium - 1x 200mcg (*)
• The normal-weight insulin resistant individual will have to take care of inflammation, (usually) a beginning fatty liver and not taking the next step to the obese diabetic.
• Berberine - 3x 200-400mg 
• Chlorogenic acid - 3x 200-300mg
• Taurine - 3x 2-3g
• Milk thistle - 3x 200-400mg
• The cheater can be either of the former or a healthy perfectly insulin sensitive individual who wants to reduce the sudden rise in blood glucose after a meal.
• Cinnamon - 1-6g (Ceylon cinnamon)
• Vinegar - 2x tablespoons
• Green tea - 1-2 cups

The insulin resistant obese / overweight individual needs relieve most urgently, therefore he will also trial fucoxanthin, which has some impressive, but not exactly reliable weight loss data. He will either have a script for metformin or will use alpha lipoic acid (ALA) as a substitute and he will make sure that he gets adequate chromium by taking 200mcg of chromium picoliante or niacin-bound chromium per day *if this is not already in a multi he or she is taking.

The normal-weight insulin resistant individual has slightly different needs than his overweight comrade. He or she is almost certainly suffering from chronic inflammation and beginning or existing NAFLD (the obese will have that, as well, but for him it's only part of the problem). With it's effects on both AMPK and PPAR-gamma berberine will make sure that the body fat levels remain low. Just like taurine (read more), chlorogenic acid (Panchal. 2012) and milk thistle (read more), it will also help "revive" the liver and sooth the inflammation by promoting the bodies own antioxidant defense system.

The cheater, on the other hand, could be everyone who wants to undo (or fore-do, if you will) a high GI carb meal. The ingredients of this stack will ameliorate the blood sugar response and could thus potentially reduce any damage you could do to your pancreas... but let's be honest. With the occasional cheat you are not going to do any damage and if cheating becomes common practice you violate the "lifestyle-changes first!" principle and won't get away healthily no matter how much supplements you take.

Browse previous articles:

Lifestyle Changes

ALA, GABA, Taurine & Co.

Berberine, Banaba & Co.

Cinnamon, Curcumin & Co.

Lemon, Starch, Coffee & Co.

Chlorogenic acid, fucoxanthin & Co.

References:

• Fedor DM, Adkins Y, Mackey BE, Kelley DS. Docosahexaenoic acid prevents trans-10, cis-12-conjugated linoleic acid-induced nonalcoholic fatty liver disease in mice by altering expression of hepatic genes regulating fatty acid synthesis and oxidation. Metab Syndr Relat Disord. 2012 Jun;10(3):175-80.
• Huang TH, Teoh AW, Lin BL, Lin DS, Roufogalis B. The role of herbal PPAR modulators in the treatment of cardiometabolic syndrome. Pharmacol Res. 2009 Sep;60(3):195-206.
• Moini H, Tirosh O, Park YC, Cho KJ, Packer L. R-alpha-lipoic acid action on cell redox status, the insulin receptor, and glucose uptake in 3T3-L1 adipocytes. Arch Biochem Biophys. 2002 Jan 15;397(2):384-91.
• Neschen S, Morino K, Rossbacher JC, Pongratz RL, Cline GW, Sono S, Gillum M, Shulman GI. Fish oil regulates adiponectin secretion by a peroxisome proliferator-activated receptor-gamma-dependent mechanism in mice. Diabetes. 2006 Apr;55(4):924-8. 
• Panchal SK, Poudyal H, Waanders J, Brown L. Coffee extract attenuates changes in cardiovascular and hepatic structure and function without decreasing obesity in high-carbohydrate, high-fat diet-fed male rats. J Nutr. 2012 Apr;142(4):690-7.
• Toomey S, Harhen B, Roche HM, Fitzgerald D, Belton O. Profound resolution of early atherosclerosis with conjugated linoleic acid. Atherosclerosis. 2006 Jul;187(1):40-9. Epub 2005 Sep 22.

Fighting to Stay Lean? These 20+ Anti-Obesity Agents Have the Potential to Inhibit Fat Gain Right at the Cellular Level

No, none of the 20 agents in the list below is going to do the work for you, but they could help you "conserve" the results, keep you lean on a bulk and/or avoid the hazardous Yoyo effect when you go off a die.

It's actually normal that the introduction is the last part of an article I write. What's special about today's SuppVersity article is thus not that I write the introduction at the end, but that I did not really know what I would be writing here, when I set out to compile the unsorted (but not chaotic) list of potential anti-obesity agents below. All of them act by pathway(s) you as a SuppVersity reader will have read about before, most prominently AMPK, and the peroxisome proliferator receptors (PPARs), of which the blockade of the obesogenic PPAR-gamma pathway, which is the main working principle of CLA turned out to be the go-to explanation for the ability of these agents to block both the differentiation of adipocytes and the storage of triglycerides in existing fat cells.

20 more or less proven anti-obesity agents for the weekend

As you are about to see, the list, which was never intended to be complete, got pretty and I guess I could add a couple of additional items, if I spent more time digging. In order not to steal your and waste more of my precious time on this sunny (finally!) Sunday, I did yet decide to call it a day, when I hit the 20-items mark. Now it's up to you to invest some of your sunny Sunday time, to read up on the details. 

• On a side note: The "holy" vitamin D does the exact opposite, if you incubate preadipocytes with 25(OH)D(3) this will lead to a significant increase in the active 1,25(OH)(2)D(3) and enhanced adipogenesis in primary mouse. Reason enough for a group of Thai researchers to conclcude that "vitamin D status may [actually] regulate human adipose tissue growth and remodeling." (Nimitphong . 2012)
  Vitamin A - Retinoic acid upregulates the expression of the adipogenesis inhibitors Pref-1, Sox9, and Kruppel-like factor 2 (KLF2) to "suppress adipogenesis in vivo and that the activity significantly contributes to the ability of the hormone to counteract diet-induced obesity." (Berry. 2012) Previous studies have also shown that all-trans-retionic acid directly increases the activity of PPARbeta/delta and so that Berry & Noy conclude "RA may be a uniquely efficacious agent in the therapy and prevention of the metabolic syndrome." (Berry. 2009) Similar results have been reported and conclusions have been drawn by Brun et al. and Sagara et al. (Brun. 2012; Sagara. 2013). Finally, Hisada et al report that - just like testosterone (learn more) - retinoic acid ensures that mesenchymal stem cells (MSCs) become osteoblasts (bone precursor cells), not fat cells (Hisada. 2013).

• Bromocriptine - If you do know it at all, then probably for it's ability to decrease the "milk hormone" prolaction. If you take a look at the broad spectrum of physiological effects of prolactin, the effect it has on the mammalian mammary gland is really negligible. A recent study from the Department of Biotechnology at the Daegu University in The Republic of Korea does now suggest that the inhibition of adipogenesis (formation of new fat cells) and lipogenesis (storage of lipids in existing fat cells) via decreased expressions of the adipogenic activators Pparα, Pparγ, and Cebpα, as well as major lipogenic target genes, including Me1, Acc1, 6Pgd, Fasn, and Prkaa1 is one of these "auxiliary functions" (Mukherjee. 2013)

• 

  EC also boosts erectile performance and testosterone (learn more)

  Ecklonia cava (EC) - or rather the dioxinodehydroeckol (DHE) molecules that are contained in this type of brown seaweed "exert[s] its anti-adipogenic effect on adipocyte differentiation through the activation and modulation of the AMPK signaling pathway" (Kim. 2010a). As a SuppVersity reader, you will be aware that this effect has been confirmed in in-vivo studies, later on (learn more).
  
  What's probably Interestingly DHE is not the only anti-adipogenic agent in brown sea algae, Fucoidan, a sulfated polysaccharide from brown seaweeds has likewise been reported to affect the development of adipocytes. In 2010, Kim et al. were able to show that it targets the MAPK kinase pathway by inhibiting the the expression of both early CCAAT-enhancer-binding proteins alpha (C/EBPalpha) and peroxisome proliferator-activated receptors gamma (PPARgamma), as well as the late activating protein 2 (aP2) adipogenic transcription factors (Kim. 2010b).

• Curcumin - While you my get the impression there was nothing curcumin cannot do (learn more), I am not whether the anti-PPAR gamma effects of curcumin are a result of it's anti-inflammatory effects or not... be that as it may, Lee et al. have demonstrated in 2009 already that the stimulatory effect curcumin exerts on the AMPK expression of adipocytes results in a down-regulation of PPAR-gamma in 3T3-L1 adipocytes (Lee. 2009).

• Resveratrol - Similar popularity, similar "cures it all" status and similar effects on AMPK and downstream PPAR-gamma expression in 3T3-L1 adipocytes... actually I would not need another bulletin point for resveratrol which acts by the exact same pathway(s) s curcumin to inhibit fat cell differentiation (Chen. 2011)

• 

  Creatine RT by Athletic Edge Nutrition; contains a cousin of ASL and is supposed to be another "super creatine" -  True or False? The 2011 SuppVersity article has the answer (read it!).

  Artemisia sacrorum Ledeb. (ASL) - Extracts from the small shrub have been used in Oriental Medicine for centuries, in 2011 Yuan et al. were able to show that ASL "down-regulate[s] the adipogenesis-related gene expression of the sterol regulatory element-binding protein 1c (SREBP1c) and its target genes, such as fatty acid synthase (FAS), stearoyl-CoA desaturase 1 (SCD1) and glycerol-3-phosphate acyltransferase (GPAT) in a concentration-dependent manner" (Yuan. 2011) The effects are meediated by a reduced expression of the peroxisome proliferator-activated receptor γ (PPARγ) and of the CCAAT/enhancer binding protein-α (C/EBPα), both of which are key transcription factors in adipogenesis.
  
  With the concomitant reduction in adipocyte fatty acid binding protein (aP2) gene expression, ASL is another potential anti-obesity agent of which Yuan et al. propose that it works its  anti-adipogenic magic via AMPK activation. In view of the fact that the same is true for the fat accumulation in human liver cells, it could serve a viable tool "in the prevention of serious diseases such as fatty liver and type-2 diabetic mellitus" (Yuan. 2010). Related increases in fatty acid oxidation have been observed in a rodent study by Hong later in 2009 with another variety of Aertemisia, namely Artemesia Capillaris (Hong. 2010). The human equivalent dosage in this trial wast 8mg/kg of the ethyl acetate fraction of the shrub.

• Phosphorylated glucosamine - While you will probably remember that large doses of regular glucosamine have been associated with insulin resistance (see previous installment of "True Or False"), it's phosphorylated variety glucosamine-6-phosphat (PGlc), Kong et al. synthesized using methanesulfonic acid, phosphorus pentoxide (P(2)O(5)), NH(2)NH(2) and DMF "significantly reduced lipid accumulation during adipocyte differentiation and induced down-regulation of peroxisome proliferator-activated receptor-gamma, sterol regulatory element binding protein 1 and CCAAT/enhancer binding protein-alpha in a dose-dependent manner." (Kong. 2010)
  

  

  Phosphorylated glucosamine works (like most of the anti-obesity agents, including the well-known conjugated linoleic acid by reducing the expression of PPAR-gamma (left). It's dose-dependent effects are yet not restricted to the peroxisome proliferator receptor, but affect the pro-adipogenic genes C/EBP-alpha and SREBP1, as well (right; Kong. 2010)

  What's also worth mentioning is that the in-vitro study from the Marine Bioprocess Research Center at the Pukyong National University in South Korea also revealed that PGcl also hampered the maturation of pre-adipocytes by down-regulating adipocyte-specific gene promoters such as adipocyte fatty acid binding protein, fatty acid synthase, lipoprotein lipase and leptin. In conjunction "[t]hese results suggest that the inhibitory effect of PGlc on adipocyte differentiation might be mediated through the down-regulation of adipogenic transcription factors, such as peroxisome proliferator-activated receptor-gamma, sterol regulatory element binding protein 1 and CCAAT/enhancer binding protein-alpha, which are related to the downstream adipocyte-specific gene promoters" (Kong. 2010) 

• 

  Add. reads: "Temporary +100kcal/Day Cold Thermogenesis Response W/ Exotic Ginger Extract" (more) "250-1000mg of Freeze-Dried Ginger Reduce Visceral Fat Even When Rodents Are Fed an Obesogenic High Fat Diet" (more).

  6-gingerol (6G) - The active ingredient in ginger has just been shown to block the obesity effects of the anti-diabetes med rosiglitazone (Tzeng. 2013). It does so by blocking the PPAR-gamma mediated effects of the "store the superfluous energy as body fat"-drug and was thus able to suppress the oil droplet accumulation and reduce the sizes of the droplets in the course rosiglitazone(RSG)-induced adipocyte differentiation in 3T3-L1 cells. Since it also blunted the increased levels of mRNA and protein in adipocyte-specific fatty acid binding protein 4 and fatty acid synthase induced by RGZ, it can be expected that 6G will not only inhibit the accrual of new, but also the (re-)filling of existing fat cells. 

• Piperine and capsaicin - In view of the fact that piperine is a "quasi-cousins" of 6-gingerol, it is actually not really surprising that it shares similar effects on the expression of PPAR-gamma (Park. 2012). It is therefore not surprising that the third member of this spicy triumvirate, i.e. capsaicin, shares the exact same PPAR-gamma reducing effects (Joo. 2010).

• Berberin - Contrary to many other items on the list, berberin's anti-PPAR-gamma effects are actually pretty well-known. There is ample evidence from in-vitro (Huang. 2006; Liu. 2009) and in-vivo (Lee. 2006) evidence that it blunts fat gain by increasing the catabolism of high energy intermediates, upregulating AMPK, modulating the expression of the GATA-2 and 3 gene and reducing the expression of (you guessed it) PPAR-gamma (Hu. 2009).

  

  Table 1: Berberine content of various commercially available supplements (Brown 2008)

  Berberine has also been shown to improve endothelial function in man (Wang. 2009) and promote the "longevity and mitochondrial health gene" SIRT1 in obesity ridden, insulin resistant skeletal muscle (Gomes. 2012).

• Ginsenosides (spec. ginsenoside Rg3) - Just like ginereol (see above) ginsenoside Rg3 has been shown to block the adipogenic effects of the anditiabetic drug rosiglitazone via an AMPK/PPAR-gamma dependent pathway (Hwang. 2009). It may be worth mentioning that at least the effect triglyceride storage was not dose-dependent. Once  a threshold amount of 40µM was reached, the adipocytes that were incubated with Rg3 did not "lose" any additional triglycerides, when the dosage was increased to 80µM.

• On a side note: Although promoted in the same health and longevity circles as CAPE, the hailed "telomerase lengthener" Astraglaus is a PPAR-gamma promoter and will thus "enhance the accumulation of lipid drops, and increase the terminal differentiation of preadipocytes" (Liu. 2007)
  Caffeic acid phenethyl ester (CAPE) - You've heard about the anti-inflammatory, muscle protective ability of this compound from bee propolis only recently (go back). In addition to being a potent anti-inflammatory, the natural phenolic compound that's also found in a variety of plants, has also been found to block the conversion of mouse fibroblasts into fat cells (Juman. 2010). As for most of the other agents the effects of CAPE appear to be mediated by a reduction inperoxisome proliferator-activated receptor (PPAR) gamma and CCAAT/enhancer-binding protein (C/EBPalpha) and concomittant reduction isn fatty acid synthetase and the expression of adipocyte-specific fatty acid binding protein (aP2). 

• Lysimachia foenum-graecum (LFE) - LFE is a Chinese herb and well-known anti-inflammatory from Oriental Medicine. The anti-obesity effect of L. foenum-graecum extract was first discovered by Seo et al., when they simply screened a whole host of potential natural agents for their anti-adipogenic effects. In 2011 the researchers found that "LFE blocked the differentiation of 3T3-L1 preadipocyte in a dose-dependent manner with an IC50 of 2.5 μg/ml". The underlying mechanism which has also been observed in an in-vivo rodent study with 100 mg/kg/day, are - how else could it be - mediated by the inhibition of PPARγ and C/EBPα expression.

  

  Effects of the administration of an lysimachia foenum-graecum ethanol extract on lipid and glucose metabolism and adipokine signalling in mice on an obesogenic diet (Seo. 2011)

  Moreover, LFE stimulated fatty acid oxidation in an AMPK-dependent manner, greatly improved serum levels of obesity-related biomarkers such as glucose, triglycerides, and adipocytokines leptin, adiponectin, and resistin and lead to an effective decrease in total body weight gain in mice who received 30, 100, and 300 mg/kg/day of an Lysimachia foenum-graecum ethanol extract (50:6; LFE) in addition to their obesogenic high fat diet (see figure above). The mice in the HFD + LFE group did simply have lower body weights, they also had a reduced amount of adipose tissues especially within the metabolically active and highly unhealthy abdominal subcutaneous, epididymal, and perirenal adipose tissue.

• 

  Photos of the lean (A and D), HFD-fed (B and E) and HFD-fed + SRLE supplemented (C and F) mice in the Thounaojam study (2011).

  Sida rhomboidea. Roxb leaf extract (SRLE) - SRLE does only sound like the stuff many supplement companies used after the ban of mua huang (natural source of ephedrine). It is however a different variety of Sida (Batyάlaka, Sida cordifolia)... well, at least it is from the same family which lacks the CNS stimulating activity of mua huang. With its ability to prevent high fat diet (HFD) induced visceral adiposity by down-regulation of PPARγ2 and leptin gene expression it could in fact work synergistically with ephedrine, though. After all the HED of the 24% w/w water extract Thounaojam et al. used to prevent the obesogenic effects of a hypercaloric high fat diet in their rodent study amounts to no more than ~40mg/kg and since SRLE has been shown to be non-toxic up to 3g/kg (in mice; HED ~240mg/kg) it would be interesting to see studies that probe whether it works in humans (Thounaojam. 2011).

• SH21B is an anti-obesity composition composed of seven herbs: Scutellaria baicalensis Georgi, Prunus armeniaca Maxim, Ephedra sinica Stapf, Acorus gramineus Soland, Typha orientalis Presl, Polygala tenuifolia Willd and Nelumbo nucifera Gaertner (active ingredients; see figure below) that has been used for the treatment of obesity in traditional medical clinics in Korea and has recently been shown to decrease the expression of major transcription factors of the adipogenesis pathway and result in the down-regulation of lipid metabolizing enzymes involved in the transport, uptake and synthesis of lipids - unfortunatedly, only in vitro (Lee. 2009)

  

  Effects of SH21B on fat droplet formation in 3T3-L1 cells (top) and size of adipocytes in adipose tissue. (bottom), as well as active ingredients in SH21B (based on Lee. 2009)

  As you can see in the stains from the adipose tissue of the above, the effects are clearly mediated by both an inhibition of the maturation of preadipocytes (top) and the inhibition of fat storage... now you tell me the world needs "new" anti-obesity agents!? I mean, it's quite obvious that the Koreans knew all along what keeps you lean ;-)

• Lactobacillus plantarum KY1032 cell extract - Before you begin to jubilee about the triumph march of probiotics, let me tell you this: I am not sure how on earth the remnants of a gut bacterium are supposed to reach your adipocyte tissue in a healthy individual without a leaky gut. Against that background I am not sure, whether it is even necessary to mention that Park et al. observed in 2011 that a cell exctract of the KY1032 strain of lactobacilli is another compound that can down-regulate the expression of peroxisome proliferator-activated receptor-γ2, CCAAT/enhancer binding protein-α, fatty acid synthase, and adipocyte-fatty acid binding protein and thus blunt fat gains in vitro... ah, now I wrote it down, so I'll just leave it here ;-) 

• Irvingia gabonensis seed extract - Likewise not a newcomer to the supplement the African / Southeast Asian tree, respectively an extract from its seeds has been shown to dose-dependently decrease the expression of PPAR-gamma in murine adipose cells in the petri dish in a 2008 study by scientists from  Faculty of Science, University of Yaoundé in Cameroon and the Wake Forest University School of Medicine in Winston-Salem, USA (Oben. 2008).

The in-vitro study shows, CAF may inhibit fat storage, but it does not "squeeze" the fat out of the cells (data based on Kim. 2012)

• Citrus aurantium falvenoids (CAF)- Despite the fact that most of you will probably have realized in N=1 experiments that citrus aurantium is a supplemental non-starter as a fatburner. It has (in-vitro) the ability to reduce the epxression of C/EBPβ and subsequently inhibit the activation of PPARγ and C/EBPα. So unless you have taken tons of pure CAF supplements during your last bulk, it is no wonder that you did not realize any effect from the fat burner you bought last summer. After all you are not storing any fat when you are dieting anyway... and I guess you have been dieting, when you took that product, right?
  
  Apropos dieting, the data in the figure on the right also shows that citrus aurantium, alone, won't help with that. After all it lacks the ability to increase LPL and thus the release of free fatty acids from the triglyceride stores in your fat stores.

• Silibinin (from milk thistle) - You will probably have heard that milk thistle can help replenish the antioxidative defenses of your liver and thus prevent all sorts of systemic toxicities (learn more). At least in-vitro silibinin (aka silybin), the major active ingredient in silymarin, can also prevent the accumulation of triglycerides in existing, as well as the formation / maturation of future adipocytes. From a mechanistic point of view, the effect is mediated by the usual suspects respectively their downregulation (CAAT/enhancer binding protein-alpha, fatty acid synthase, sterol response element binding protein 1c, adipocyte-specific lipid binding protein, peroxisome proliferator-activated receptor gamma and lipoprotein lipase; cf. Ka. 2009).

• Stem bromelain (SBM) - Just as so many of the previously mentioned agents, SBM, a specific member of the bromelain family you may know as "pineapple enzyme", is by no means a "new kid on the anti-fatloss block". Rather than that it has been used for centuries in traditional medicine as - guess what? - an anti-obesity agent. Now, I would never suggest that all TCM medicines work, but for stem bromelain it does at least seem as if the in-vitro studies, Dave et al. conducted about a year ago would support the notion that the ingestion of respective supplements can in fact exert beneficial effects on the accumulation of body fat (Dave. 2012).

  

  Illustration of the mechanism and selected downstream effects of stem bromelain (SBM) on fat cells in the petri dish (compiled based on data from Dave. 2012)

  At the molecular level, SBM targets the same adipogenesic genes as (almost all) of the previous agents. What's interesting though, is the fact that the scsientists also found that "SBM's ability to repress PPARγ expression seems to stem from its ability to inhibit Akt and augment the TNFα pathway." (Dave. 2012) In other words, it's the increase in "bad" TNF-alpha and the decrease in the purportedly muscle, but in fact simply "mass building" Akt-TSC2-mTORC1 pathway that entails the apoptosis (controlled cell death) of mature adipocytes and lipolysis.

With the stem bromelain this comprehensive, but by no means all-encompassing list of "proven" (mostly only in vitro) anti-adipogenic agents, has come full circle. After all, Dave et al. point out that their data would indicate that stem bromelain, together with all-trans retinoic-acid (atRA), which is a metabolite of vitamin A, the first item on our list "may be a potent modulator of obesity by repressing the PPARγ-regulated adipogenesis pathway at all stages and by augmenting TNFα-induced lipolysis and apoptosis in mature adipocytes." (Dave. 2010).

It's not just beyond the scope of this article, but - in the majority of the cases simply not known - whether or not the TNFα increase is an integral part of the anti-obesity effects of all of the aforementioned compounds. As far as the inhibition of PPAR-gamma is concerned things are different, though. With PPAR-gamma being the central "fat storage" switch, its deactivation and the entailing blockade of adipocyte differentiation, pre-adipocyte maturation and triglyceride storage is currently probably the most effective anti-obesity  mechanism we know. A mechanism that is way more fundamental than the diet-induced and stimulant / alpha/beta-agaonist (caffeine, ephedra, clenbuterol, yohimine) supported emptying of existing adipocyte triglyceride stores.

---

I know it's not popular, but in the case of vitamin D we already have evidence of it's obesity promoting effects (read more). It's straight forward experimental evidence, much contrary to the epidemiological guesswork on the basis of which people are popping vitamin D pills, these days.

Keep in mind: Most of the data is derived from in-vitro studies. Few compounds do have actual evidence from rodent studies and the number of substances that showed beneficial effects in human studies is even smaller.

Nevertheless, the above list harbors a number of compounds which could be of great interest for the lean physical culturist, for whom (at least physique-wise) stuff like vitamin D (note: the effects could be dose-dependent with benefits at low, and detrimental effects at high levels), astragalus and the rest of the healthy, but pro-adipogenic agents that can help obese individuals to stash away the tons of sugar and fat floating through their arteries are of little use.

Against that background I want to close this post with a warning, or I should say a reminder of the the fact that the effects of PPAR-gamma are physiologically important (e.g. prevention of lipotoxicity, Medina-Gomez. 2007) and go beyond "just making you fat" in how it would be worth striving to suppress it altogether is thus questionable (suggested read: CLA Destroys Body Fat). Since for all of the previously discussed agents that have in-vivo data to support their efficacy have postivite, not negative "side effects" (think of curcumin, gingerol, ginseng, etc.), it is yet unlikely that the use of reasonable amounts of one or a stack of many of them is going to harm you.

Just keep in mind: The goal should be to keep the PPAR-gamma activity in check, not to annihilate it. Consequently you should not and cannot expect to be able to "eat whatever you want and still stay lean" by supplementing with any of the agents above. On the other hand, they can hardly be even less useful than the vast majority of currently available arsenal of OTC "fat burners" ;-)

References:

• Berry DC, Noy N. All-trans-retinoic acid represses obesity and insulin resistance by activating both peroxisome proliferation-activated receptor beta/delta and retinoic acid receptor. Mol Cell Biol. 2009 Jun;29(12):3286-96.
• Berry DC, DeSantis D, Soltanian H, Croniger CM, Noy N. Retinoic acid upregulates preadipocyte genes to block adipogenesis and suppress diet-induced obesity. Diabetes. 2012 May;61(5):1112-21. 
• Brown PN, Roman MC. Determination of hydrastine and berberine in goldenseal raw materials, extracts, and dietary supplements by high-performance liquid chromatography with UV: collaborative study. J AOAC Int. 2008 Jul-Aug;91(4):694-701.
• Brun PJ, Yang KJ, Lee SA, Yuen JJ, Blaner WS. Retinoids: Potent regulators of metabolism. Biofactors. 2012 Dec 22. doi: 10.1002/biof.1056. 
• Chen S, Li Z, Li W, Shan Z, Zhu W. Resveratrol inhibits cell differentiation in 3T3-L1 adipocytes via activation of AMPK. Can J Physiol Pharmacol. 2011 Nov;89(11):793-9.
• Gomes AP, Duarte FV, Nunes P, Hubbard BP, Teodoro JS, Varela AT, Jones JG, Sinclair DA, Palmeira CM, Rolo AP. Berberine protects against high fat diet-induced dysfunction in muscle mitochondria by inducing SIRT1-dependent mitochondrial biogenesis. Biochim Biophys Acta. 2012 Feb;1822(2):185-95.
• Hisada K, Hata K, Ichida F, Matsubara T, Orimo H, Nakano T, Yatani H, Nishimura R, Yoneda T. Retinoic acid regulates commitment of undifferentiated mesenchymal stem cells into osteoblasts and adipocytes. J Bone Miner Metab. 2013 Jan;31(1):53-63.
• Hong JH, Hwang EY, Kim HJ, Jeong YJ, Lee IS. Artemisia capillaris inhibits lipid accumulation in 3T3-L1 adipocytes and obesity in C57BL/6J mice fed a high fat diet. J Med Food. 2009 Aug;12(4):736-45.
• Hu Y, Davies GE. Berberine increases expression of GATA-2 and GATA-3 during inhibition of adipocyte differentiation. Phytomedicine. 2009 Sep;16(9):864-73. doi: 10.1016/j.phymed.2009.03.002. Epub 2009 Apr 28.
• Huang C, Zhang Y, Gong Z, Sheng X, Li Z, Zhang W, Qin Y. Berberine inhibits 3T3-L1 adipocyte differentiation through the PPARgamma pathway. Biochem Biophys Res Commun. 2006;348:571–578.
• Hwang JT, Lee MS, Kim HJ, Sung MJ, Kim HY, Kim MS, Kwon DY. Antiobesity effect of ginsenoside Rg3 involves the AMPK and PPAR-gamma signal pathways. Phytother Res. 2009 Feb;23(2):262-6.
• Joo JI, Kim DH, Choi JW, Yun JW. Proteomic analysis for antiobesity potential of capsaicin on white adipose tissue in rats fed with a high fat diet. J Proteome Res. 2010 Jun 4;9(6):2977-87.
• Juman S, Yasui N, Okuda H, Ueda A, Negishi H, Miki T, Ikeda K. Caffeic acid phenethyl ester inhibits differentiation to adipocytes in 3T3-L1 mouse fibroblasts. Biol Pharm Bull. 2010;33(9):1484-8.
• Ka SO, Kim KA, Kwon KB, Park JW, Park BH. Silibinin attenuates adipogenesis in 3T3-L1 preadipocytes through a potential upregulation of the insig pathway. Int J Mol Med. 2009 May;23(5):633-7.
• Kim SK, Kong CS. Anti-adipogenic effect of dioxinodehydroeckol via AMPK activation in 3T3-L1 adipocytes. Chem Biol Interact. 2010a Jun 7;186(1):24-9.
• Kim KJ, Lee OH, Lee BY. Fucoidan, a sulfated polysaccharide, inhibits adipogenesis through the mitogen-activated protein kinase pathway in 3T3-L1 preadipocytes. Life Sci. 2010b May 22;86(21-22):791-7.
• Kim GS, Park HJ, Woo JH, Kim MK, Koh PO, Min W, Ko YG, Kim CH, Won CK, Cho JH. Citrus aurantium flavonoids inhibit adipogenesis through the Akt signaling pathway in 3T3-L1 cells. BMC Complement Altern Med. 2012 Apr 3;12:31.
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