The Fallacy of Working Out To "Burn Calories" + Exercise Shuts Down the Carb Cravings: Bench Press, Leg Press HIIT & LISS Are Not Meant to Incinerate the Junk You Eat

If you work out to be able to allow yourself to eat, you know you have a serious problem.

So, what was that about the bench pressing consuming as much energy as leg presses and the "exercise just makes you hungry myth" on the last installment of the Science Round-Up? If that's what you have been asking yourself this morning, when you showered I am impressed - or should I be worried?

If you have not done so already, this would be the right time to download + listen to the Science Round-Up - I promise there is much to learn and not all of it is going to be repeated here.

Whatever... in the end it does not matter how urgent you were waiting to take a look at the data that supports my argument that (a) exercise does not just make you hungry, and that (b) the notion to work out primarily to burn energy is hilarious.

Chest vs. legs what's energetically more costly?

While I could imagine that the comparison would have yielded a different result if the 10 healthy young men (>1 year of resistance training experience; BMI ~24kg/m²) had performed squats instead of regular leg presses, I have to admit that I was still surprised to see that Magossoa et al. actually found no difference in the total energy expenditure between 3 sets of 10 reps (70% 1RM) of bench vs. leg presses (Note: The researchers determined the total energy expenditure using the oxygen uptake (aerobic component) the EPOC and lactate production (anaerobic component)).

Table 1: Workload, energy expenditure total, per minute per weight lifted (Magosso. 2013)

If you look at the data in Table 1, you will have to concede: The only difference between the energy expenditure during the leg and the leg press was the inferior energy consumption per kg of weight on 'the bench'.

If you were one of the lazy (and mostly ignorant) buggers who "already have big enough legs", you could probably use these results to argue that leg presses and the rest of the leg workout was a pretty unnecessary undertaking - I mean, if you don't want bigger legs it should at least help you with that sixpack by burning a couple of calories, right?

Only a fool will work out to "burn energy"

Suggested Read: "Busting the 3,500kcal = 1lbs Weight Loss Myth! Debunking the rule of thumb with the power of science" | read more

Once they're there, it does usually you not take very long until people will remember this ingeniously simply (and about s flawed) rule of thumb that says: To lose 1lbs of fat you got to burn 3,5000kcal. Here, in our concrete example, that would mean that it would not matter if you did another 228 sets of bench presses or leg presses to lose 1lbs of pure body fat.

Once you've gotten caught in calculations such as the above, i.e. 229 sets x 46kcal / 3 sets  > 3500kcal, or in words "I got to do 228 sets of bench presses to burn one pound of body fat!", you are lost.

Firstly, the equation 3,500kcal caloric deficit = 1lbs fat loss if flawed (learn more).

Secondly, and even more importantly, doing more, which is what all the "I workout to lose fat" weekend warriors do, is not going to yield superior results. If you don't believe that, I suggest you go back to my "How to Burn 27,300 Kcal Extra W/out Losing a Single Extra Pound of Fat!"-article and take a look at the results of the Rosenkild study from 2012 (figure 3).

Gary is ... no, not a fool, but he is still wrong

Now, I obviously cannot forbid workout extra and luckily even Gary Taubes can't because even if you insisted to burn 600kcal, instead of just 300kcal, you can at least console yourself that this is not going to increase your appetite (learn more). Especially if we are talking about relatively intense exercise for similarly "relatively obese" individuals, working out will not only reduce your window of opportunity to eat (for some people even that may make a difference, believe me), but rather work like a gastric bypass - one that won't allow you to hit your obesogenic macros on the subsequent meals.

Figure 1: Macronutrient intake (lunch + dinner in g) on control vs. exercise day (David. 2013)

Those of you who have not listened to the podcast yet will now probably be wondering what I am talking about, right? Well, take a look at the 3D bars in Figure 1. They represent the results of a study David et al. conducted earlier this year. A study that involved both lean and obese kids and a study that demonstrates that a relatively short (3x10 min) but comparably hard workout (75% VO2max) is not going to make the sugar junkies crave for more - quite the opposite, it will reduce their apperite for carb(age) to a normal level [similar appetite-reducing effect were observed by Sim et al. (2013) in adult men and Rosenkilde (2013; already discussed at the SuppVersity].

I mean, a voluntary 35% reduction in carbohydrate intake during lunch and dinner and a total reduction in energy intake of 475kcal are impressive ballpark figures considering the fact that exercise is often said to "just make you hungry" - wouldn't you agree?

EPOC should not determine your choice of exercise either

If you are sprinting because of the increase in EPOC, you are a fool.

From the article I referenced in yesterday's write-up ("More Than 3x Higher EPOC Induced Energy Expenditure With HIIT vs. LISS! But Does That Really Matter?" | read more) you already know that  HIITing it hard on Wingate tests will yield a pretty pathetic increase in EPOC of ~20kcal over a casual 30min jog.

So even if it was about burning calories the jog would be far superior because the increase in Excess Post-Exercise Oxygen Consumption (EPOC) is not going to compensate the additional kcal the subjects in the Townsend study burned during the steady state exercise.

The latter is by the way not much different if you compare two different HIIT regimen - a very intense short one (HIIT1) and a somewhat longer slightly less intense alternative regimen (HIIT2):

• HIIT1: 10 x 1min, 1min pause between intervals; cycling at 80-90RPM at 90% of the HRmax

• HIIT2: 10 x 4min, 2min pause; cycling at 60-80RPM and without a prescribed minimal heart rate

In their trial that involved 9 lean, healthy male subjects, Kelly et al. obeserved that the HIIT2 trial was more than two times more energetically costly (675kcal vs. 275kcal) - the EPOC effect on the other hand did not lead to any significant differences in post-exercise energy expenditure, so that the HIIT1 group was stuck with their ~400kcal inferior energy expenditure... now, that sounds as if it was a bad thing, but if we consider that they spent less time on the ergometer and were rewarded with a greater stimulus for mitochondrial expansion and even muscle growth (see "The Anablic Effects of HIIT" | read more), I would not say that they came off second best - would you?

Practical suggestions for your workout week...

• health focus - 2-3x resistance training + daily LISS as in walking (min. 30-60min)
• performance focus - 3x resistance training + 1-2x HIIT + 6x LISS as in walking (30-40min)
• physique focus - 3-4x resistance training + 1x HIIT +  6x LISS as in walking (30-40min)

Don't forget that the reason you do the LISS training is not because you want to burn calories, but rather because you want to spend some time doing what you actually would have to do everyday: Walking from place A to B; and if you belong to the few of us who don't sit on a desk all day, you may skip the walk in the park.

So what's a good reason to work out, then? Health! I know that does not sound as sexy as six-pack abs and bigger sleeves, but there is not denying it: Exercise is your vaccine and magic pill. It's what's going to make you feel good, look good and age well and unless you want to end up debilitated in a nursing home it is not optional even if you follow an energy restricted diet for the rest of your life. What is optional, though, is exercise as a means to increase athletic performance or influence the shape of you body withing your individual very specific limits.

Within this health ↔ performance ↔ looks triangle you will often encounter conflicts, where the optimization of one compromises the realization of another. I am nevertheless convinced that classic light intensity steady state (to make up for our modern sedentary lifestyle), en vogue high intensity interval training (to increase your VO2max) and classic and modern forms of resistance training (to build and maintain muscle mass) all have their place in a routine that does not lose sight of any of the vertices of the triangle.

What? How you can ever lose weight without doing endless hours of cardio? Well what about dieting?

References:

• David T, et al. Obese but not lean adolescents spontaneously decrease energy intake after intensive exercise. Physiol Behav. 2013 [epub ahead of print]
• Kelly B, King JA, Goerlach J, Nimmo MA. The impact of high-intensity intermittent exercise on resting metabolic rate in healthy males. Eur J Appl Physiol. 2013 Oct 6. [Epub ahead of print]
• Magosso et al. Energy Expenditure during Multiple Sets of Leg Press and Bench Press. Journal of Exercise Physiology online. October 2013.
• Rosenkilde M, Auerbach P, Reichkendler MH, Ploug T, Stallknecht BM, Sjödin A. Body fat loss and compensatory mechanisms in response to different doses of aerobic exercise--a randomized controlled trial in overweight sedentary males. Am J Physiol Regul Integr Comp Physiol. 2012 Sep 15;303(6):R571-9.
• Rosenkilde M, Reichkendler MH, Auerbach P, Toräng S, Gram AS, Ploug T, Holst JJ, Sjödin A, Stallknecht BM. Appetite regulation in overweight, sedentary men after different amounts of endurance exercise - a randomized controlled trial. J Appl Physiol (1985). 2013 Sep 19. [Epub ahead of print]
• Sim AY, Wallman KE, Fairchild TJ, Guelfi KJ. High-intensity intermittent exercise attenuates ad-libitum energy intake. Int J Obes (Lond). 2013 Jun 4. doi: 10.1038/ijo.2013.102. [Epub ahead of print]

Exercise: Does It Really Make You Hungry? The More You Train, The Less Hungry You Are. Still, 30 Min of Cardio Are More Productive Than 60 Min to Get in Shape

Start early and don't stop before you drop. If physical activity is a part of your life from the womb to the grave, you won't have to worry about whether cardio makes you hungry.

Friends of the SuppVersity will recognize this question as a recurring motif: "Does exercise really make you hungry?" An in case you are, you will also know that you have to blame Gary Taubes who seems in all honesty to believe that you would be able to cheat diabesity by simply leaving out the "bad calories" (=carbohydrates) for previous SuppVersity articles such as "HIT the Cravings, Eat Less and Improve Your Health", "Every Dog Has It's Day - Dr. Oz Was Right, Exercise Does NOT Just Make You Hungry" or Facebook News like this.

In the end, Gary is also to blame for today's SuppVersity news, or at least the fact that I jumped right at the results of a recent study from the University of Copenhagen (Rosenkilde. 2013)

So does it make you hungry, or what?

In the Danish capitol, Mads Rosenkilde, Michala Holm Reichkendler, Pernille Auerbach, Signe Toräng, Anne Sofie Gram, Thorkil Ploug, Jens Juul Holst, Anders Sjödin, and Bente Stallknecht conducted what I consider to be a very important study - a study that may not be changing the way we deal with the diabesity epidemic, but one that will hopefully shut those people up, who just tell the lazy ones what they want to hear: "Pah, don't bother about working out: It will just make you hungry!"

Taubes lectures Dr. Oz on "bad calories" = carbs and the perils of exercise

Interestingly, the reasearchers started out with an observation Gary Taubes made as well: "Weight loss induced by endurance exercise is often disappointing." They even come to the same conclusion as Gary did, but realize that their assumption that it may be an "increase in energy intake mediated through greater appetite" (Rosenkilde. 2013) which could explain the failure of previous weight loss trials with a focus on endurance exercise is just that: an assumption - not a given truth and thus from a scientific perspective a hypothesis that requires experimental verifi- or falsification.

When the Rosenkilde et al. recruited 64 sedentary, overweight, healthy young men for their study, they wanted to (ab-)use them to elucidate whether endurance exercise would exert any direct or indirect effects on fasting, postprandial and post-exercise appetite regulation that could precipitate their subjects to overeat and thus confirm Gary's (sorry, Mr. Taubes, I know you are not alone with this message, but you are the one people are listening to)

"Some LISS for MORE" - Do you remember?

SuppVersity Highly Suggested Read: "Some HIIT For Life & Less LISS For More! How to Burn 27,300 Kcal Extra W/out Losing a Single Extra Pound of Fat!" (read full post) - another Rosenkilde study from 2012. And a study in which the Danish researchers were able to show that a HIGH dose of endurance exercise does not produce suprerior fat loss results, even when the energy intake was controlled for and overeating not an issue!

To this ends, the Danes randomized the young men to three groups: A sedentary control group (CON), a moderate dose endurance exercise group (~30min/day; MOD) and a high dose endurance exercise group (~60min/day; HIGH). Now as SuppVersisty veteran you should by now be able to make a prediction about the outcome of the study. Anyone?

I guess you must have forgotten one of my personal favorites, then: "Some HIIT For Life & Less LISS For More! How to Burn 27,300 Kcal Extra W/out Losing a Single Extra Pound of Fat!" (read full article) - an article in which I describe (among other things) the results of a previous study by Rosenkilde that demonstrated quite clearly that a HIGH dose exercise regimen is not more effective than a MEDIUM dose exercise regimen, even if the calorie intake of the subjects was standardized.

The study period in the study at hand were 12 weeks. For the total amount of hours the subjects were running, cycling or whatever other endurance activity they chose was 12x7x30min or 12x7x60min. The exercise had to be performed at identical intensities 66% of the VO2max in all groups and with 66±1% (MOD) and 67±1% (HIGH) all subjects met this criterial.

On a per exercise session basis, the subjects in the HIGH did thus expend more almost twice as much energy as their medium dose counterparts (HIGH: 649±10 kcal vs. MOD: 338±8 kcal; p < 0.001). According to the Taubes'ian logic this must necessarily lead to an increase in appetite and, since there was no dietary prescription as in the 2012 study, a corresponding increase in energy intake.

Note: The the subjects’ adherence to the exercise regimen was excellent, with MOD having only a marginally better compliance to the prescribed amount of exercise than HIGH (MOD: 99±1% vs. HIGH: 96±1%; difference p = 0.047, i.e. non-significant).

So much about "I have not time to go to the gym!"

"Based on each subject’s VO2 max, resting and maximal heart rates (HR) and body weight, the duration of each exercise session was individually prescribed and extensively monitored via requent personal consultations with scientific staff (at least twice weekly).

The exercise prescription was based on each subject’s individual relationship between heart rate and VO2as determined by indirect calorimetry during an exercise test in the laboratory at baseline and was calibrated after the 2 nd , 6 th and 10 th intervention week based on changes in VO2max, heart rate and body weight. Compliance was verified using HR monitors (RS400, Polar Electro OY; Kempele, Finland) that stored information about the subjects’ exercise EE, intensity and duration." (Rosenkilde. 2013)

Both at baseline and at follow-up, the scientists measured the subjective appetite ratings. In addition, plasma ghrelin, glucagon, insulin, peptide YY3-36 (one of the major satiety hormones), glucose, free fatty acids and glycerol were measured during fasting and in response to a breakfast meal and an acute bout of exercise.

Figure 1: Effects on glucagon (goes up, when glucose goes down), ghrelin (hunger hormone), PYY (satiety hormone), and satiety (during breakfast condition), plus effects on body weight and composition (Rosenkilde. 2013).

As you can see in figure 1, the subjects' ad libitum lunch energy intake, which was evaluated three hours after the breakfast meal, did not differ between the endurance exercise groups. Similarly,...

[...d]espite different amounts of endurance exercise, the subjects lost similar amounts of fat mass (MOD: 4.2±0.5 kg; HIGH: 3.7±0.5 kg). Fasting and postprandial insulin decreased ~20% in both exercise groups (P<0.03 vs. CON). [And the a]ppetite measurements were not up-regulated in the fasting and postprandial states." (Rosenkilde. 2013)

So, a high dose of exercise didn't make the subjects hungry. Rather than that, the exact opposite was the case: Fasting and postprandial ratings of fullness and postprandial PYY (one of the major satiety hormones) increased in the HIGH (P<0.001 vs. CON) group to a significantly greater extent than in the supposedly less hungry MEDIUM group and reached a level that "signifies a significant satiety effect" (Rosenklide. 2013) in response to doing 60min of endurance exercise.

---

Outliers, over-eaters and general trends: Despite the fact that exercise training may have reduced the hunger and food intake for the majority of the trainees, there were 3 outliers who increased their energy intake almost 4-fold. Accoring to Rosenkilde et al., "[t]hese subjects did not display any adverse subjective appetite ratings immediately before the meal, nor was their satisfaction with the meal apparently different." Personally, I suspect that these subjects may have had blood sugar issues and were borderline hypoglycemic after the exercise. Since that happens quite easily when you cut carbs, but don't eat enough fat (and or too much protein), I guess some of you may this ravenousness very well, right?

When these subjects were excluded from the statistical analysis, the scientists observed a definite tendency towards a decrease in energy intake in the MOD as compared with CON at follow-up (-115 kcal, CI: -244:13; P = 0.08).

Bottom line: Although we should keep in mind that the overall changes in body composition may not reflect the superiority of the HIGH dose exercise regimen on the appetite ratings, hormonal markers of satiety and perceived fullness of the subjects, the results of the study at hand clearly refute the standard hypothesis of increased appetite as the main reason for the failure of endurance exercise based weight loss interventions.

In view of the previously cited results of the 2012 trial by the Rosenkilde et al., it is however not advisable to waste a whole hour of your precious time on endurance exercise everyday. While it is unquestionably possible (I know many people who do it), it's (a) tiring + boring, and most importantly, (b) stressing to jog or bike 60min every day (the stress is probably also the reason for the deterioration of the body fat levels in the 2012 study referenced previously).

In the real world, doing cardio for 60min every day will also reduce the amount of time you have to (1) do your (imho) obligatory resistance training sessions and to (2) shop and prepare whole foods meals. At least for the real busy-bodies it will also (3) steal half an hour (compared to doing less cardio) of your life-time you could better spend sleeping (for both general health and weight loss reasons). Nevertheless, it is not a reason to "overeat" for the average dieter and my personal observations tell me: Those who make it to the gym for their cardio sessions everyday have not the least problem to starve themselves; and the study at hand suggests this may (partly) be because of, not despite doing all that "cardio"!