Protein - 0.8g/kg Insufficient for Female Athletes, Too. Plus: Revised RDA is 1.71-2.2 g/kg/d Depending on Sport & Sex

With average daily protein intakes of only 90±24 g (Gillen 2017), many female athletes are probably missing the sweet spot of ~1.7g/kg/d.

I guess I am preaching to the choir when I write that the recommended daily allowance (the magical "RDA") for protein is laughable; the number of studies which show that an increased protein intake will have beneficial metabolic effects is increasing by the day; the subjects of these studies are men and women, kids, teens, tweens, adults, and grandparents, perfectly healthy or sick, lean or fat... and in all of these increasing the protein intake to ~2x the RDA of 0.8g/kg has been found to be associated with significant beneficial effects on body composition and/or health in the majority of the studies (learn more).

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Unfortunately, humans lack a measuring gauge that would allow us to decide when we've satisfied our daily protein requirements and/or consumed the optimal amount of protein. I guess this is also why we don't even know for sure how exercise will affect our protein need. Yeah, we do have plenty of evidence that extra protein will augment size and strength gains in resistance training and, with the publication of pertinent studies, even endurance trainees are now jumping aboard the "protein supplementation wagon" (learn more).

Stuart M. Philips and colleagues are among those researchers who have been dabbling with the idea of increased protein requirements in athletes and non-athletes, young and old, sick and diseased for years (Phillips 2007; Phillips 2017). As the Canadian scientists point out in one of their latest reviews (Phillips 2017), there are two main methods to measure human beings protein balance. There is...

• measurement of an individual's nitrogen balance - This method has been used for more than 60 years, despite its various shortcomings (Young 1986); and it is also the methodology that underpins the "RDA", a term of which Phillips writes in his review in Front Nutr. in 2017 that it would "inherently imply that the protein intake is 'recommended,' and it is all that you are 'allowed' to eat" (Phillips 2017). Now, I don't have to quote an expert for you to understand that this is, "[o]f course, [...] strictly speaking [not] true" (ibid.). 
• the more recent alternatives are the indicator amino acid oxidation (IAAO) method and the 24h-indicator amino acid oxidation and balance method (24h-IAAO/IAAB)- Having been explicitly developed as an alternative to the nitrogen balance (free reviews can be found in Elango et al. 2008 & 2012), they yield significantly higher values for optimal protein intakes in than nitrogen balance studies, especially in older individuals.

Even though, I believe that this is the first time some of you read about this, the above ain't 'news' in the strict sense of the word and wouldn't have made it into this article, if it wasn't necessary to know that the IAAO method has recently been applied by Wooding et al. (2017) to determine a dietary protein requirement in active females performing variable-intensity intermittent exercise using the indicator amino acid oxidation (IAAO) method.

If we go by the Institute of Medicine's AMDR concept, 0.8g/kg is the absolute minimum, not the recommended protein intake.

What is currently recommended? You already know that the RDA, i.e. the "recommended daily allowance" for protein is 0.8g/kg. Despite its name, it's yet not the RDA, but the AMDR, i.e. the Acceptable Macronutrient Distribution Range that defines the "range of intakes for a particular energy source that is associated with reduced risk of chronic diseases while providing adequate intakes of essential nutrients" (Institute of Medicine 2005). The AMDR says that 10–35% of one's total energy intake should come from protein. As Phillips calculates in the previously cited study, this means that a 55-year-old man who is 1.80 m, weighing 80 kg, would not have to consume the laughable 64 g protein/day the RDA would recommend, but rather 65 g/day as an absolute minimum (that's 10% of the total energy intake and thus the lower AMDR).

Optimal intakes for our exemplary 55-year-old man, on the other hand, would be somewhere within the AMDR of 65–228 g protein/day (assuming an energy requirement of 2,600 kcal/day or 10.9 MJ/day) - in other words, the "optimal" range, i.e. the range where the Institute of Medicine says that it takes "into account the trends related to decreased risk of disease identified in epidemiological and clinical studies" is, as Phillips highlights in his previously cited review from 2017 "well above the RDA (up to 2.8 g/kg/day) that are associated with good health".

The scientists from the University of Toronto started their study with the hypothesis that these requirements would be greater than current IAAO-derived estimates in non-active adult males. And indeed, even though the IAAO method has been around for a couple of years, there's still a paucity of evidence for various populations - including female athletes participating in team sports.

We do already know that endurance athletes need more, much more ...

As Wooding et al. point out, their "group previously used the minimally-invasive indicator amino acid oxidation (IAAO) method to demonstrate that protein requirements in endurance athletes are ~50% greater than sedentary individuals" (Wooding 2017). That, however, is still a pretty conservative estimate, as it marks the protein requirements, not the optimal intakes that will "maximises whole body protein synthesis" and thus enhance recovery from, and potentially adaptation to, an exercise stimulus" (ibid.) - a value the scientists sought to determine in their latest study which involved six healthy, active young adult females (see Table 1).

Figure 1: Modified LIST in which participants followed an audio prompt to complete the variable-intensity intermittent exercise pattern 10 times per block. There were four blocks separated by 5-min breaks, totaling 75-min of exercise plus a 5-min warm-up and cool-down at a self-selected pace (Wooding 2017).

Four individuals were varsity athletes (three rowing, one ice hockey), one was a national level volleyball player, and one was a highly active recreational athlete.

"Participants were required tobe healthy (PAR-Q+), have habitual activity levels of more than 45 min/d on 5 d/wk of moderate vigorous physical activity (I-PAQ for adults aged 15-69), a predicted VO2max ≥44.6 mL O2/kg/min (Leger Multistage Fitness Test), no current use of hormonal contraceptives, and a predictable menstrual cycle (25-33d) during the previous year as determined by interviews and the participants’ records of the 2-3 months prior to study enrollment" (Wooding 2017).

Each participant completed 5-7 metabolic trials (n = 36) during the predicted luteal phase. The women consumed a 2-d adaptation diet containing 1.2 g/kg/d of protein prior to each trial. Wooding et al. chose this intake "in order to minimize metabolic variability during the trial day" and to "provide a level that was previously determined to be sufficient for non-exercising males by IAAO" (ibid.) (15). These adaptation diets contained sufficient energy to meet the subjects' individual habitual daily caloric expenditure of ~2700kcal/d.

Figure from an exemplary study by Kriengsinyos et al. (2002),

How does this strange NaH13CO2 + tracer amino acid test work? Let's take a look at the exemplary data from Kriengsinyos et al. (2002) that has been reprinted in Elango's previously cited 2008 review. Kriengsinyos et al. investigated the effect of lysine intake on the production of 13CO2 from the oxidation of L-[1-13C] phenylalanine (F13CO2) when tracer was infused either i.v. or orally in healthy adult humans (note: one of the important results of the study at hand is that the estimated protein/amino acid requirements don't differ for i.v. vs. oral administration).

As Elango et al. explain in their 2012 paper, "the IAAO technique is based on the concept that when one indispensable amino acid (IDAA) is deficient for protein synthesis, then all other amino acids including the indicator amino acid (another IDAA, usually L-[1-13C]phenylalanine) are in excess and are therefore oxidized" (Elango 2012). That's logical, after all, dietary protein can only either be stored or oxidized. If a rate limiting amino acid is missing, storage is not an option and oxidation will take place. As the intake of said limiting amino acid increases, the oxidation of the indicator amino acid will decrease -  a decrease that reflects the increasing incorporation of amino acids into protein. Yet, once the requirement is met for the limiting amino acid, there will be no further change in the oxidation of the indicator amino acid with increasing intake of the test amino acid (see breaking point in the figure). The inflection point where the oxidation of the indicator amino acid stops decreasing and reaches a plateau is referred to as the ‘breakpoint’. The breakpoint, identified with the use of two-phase linear regression analysis, will then "indicate the estimated average requirement (EAR) of the limiting (test) amino acid" (Elango 2012) - in the example from Kriengsinyos et al. (2002), the breakpoint for lysine is 36mg/kg/d.

On test days the participants reported fasting at the lab, ingested a CHO sports drink and performed a modified version of the Loughborough Intermittent Shuttle Test (LIST; cf. Figure 1), an exercise protocol that simulates the activity pattern of a soccer match:

"Briefly, the test involved four 15-min blocks in which a 17-m variable-intensity shuttle pattern was repeated 10 times with 5-min rests between each block. The entire test was 75 min in length, which also included a 5-min warm-up and cool-down at a self-selected pace. The running pace in our study was based on the percentage of average maximum speed obtained by the entire group of participants during the aerobic assessment (3.45m/s) instead of the percentage of individual VO2max. In this way, the same audio prompt was used for all participants with the following 17-m shuttle paces: 1.7m/s (walk), 2.1m/s (jog) 3.1m/s (run), and an all-out sprint. The average energy expenditure during the LIST was 8.7 ± 0.2 kcal/kg (range 8.5-9.1kcal/kg, determined from accelerometer)" (Wooding 2017). 

Following exercise, participants consumed their first of eight hourly mixed meals containing the test protein intake (0.2-2.66 g/kg/d) and sufficient energy and CHO content in the form of test beverages containing crystalline amino acids, protein-free powder, fruit flavoring powder, grapeseed oil, and maltodextrin as well as protein-free cookies. The actual measurement was done by including a priming dose of NaH13CO2 (0.176 mg/kg) and L-[1-13C]phenylalanine (1.86 mg/kg) in every hourly meal beginning at meal #5. The turnover of this tracer was determined from urinary [13C]phenylalanine enrichment.

Figure 2: Relationship between protein intake and F13CO2. Six participants completed 5-7 metabolic trials each (n=36). F13CO2 breakpoint was used to estimate protein requirements and recommended daily allowance (Wooding 2017).

The breaking point (compare explanation in the blue box above) was determined by analyzing the subjects' breath for F13CO2. As you can see in Figure 2, the F13CO2 curve displayed the expected robust bi-phase response (R² = 0.66) and points, as the author's point out, "to an estimated average requirement (EAR) of 1.41 g/kg/d and an RDA of 1.71 g/kg/d" (Wooding 2017).

Overview of new, IAAO based protein intake minimums and recommendations in different groups of athletes; the figures across the bar denote the values in units of the current RDA of 0.8  g protein /kg/d (Wooding 2017 women in team sports; Kato 2016 male endurance athletes; Bandegan 2017  bodybuilding men)

Bottom line: The study at hands provides further evidence that the well-known and repeatedly cited population guidelines which are based on net protein breakdown analyses are inadequate when it comes to the protein requirements of the athletic population, for whom contemporary sports science consensus statements suggest a broad range of protein intakes from 1.2-2.0 g/kg/d should be consumed by athletic populations (Thomas 2016).

What the study adds to the existing evidence are definite numbers for the minimal and recommended protein intake of female team-sports athletes, a subject group that is often overlooked in clinical research.

More specifically, Wooding's data reveals that an acute bout of variable-intensity exercise results in an increase of young women's protein requirements to 1.41 g/kg/d and an approximate RDA, i.e. an intake that can be expected to be sufficient for 95% of the population, of 1.71 g/kg/d. As previously hinted at, this result is consistent with the scientists' previous observations in endurance-trained males on a day in which they trained (Kato 2016) and in bodybuilders on a rested day (Bandegan 2017) - all numbers you know from the SuppVersity Facebook or Twitter News | Comment!

References:

• Elango, Rajavel, Ronald O. Ball, and Paul B. Pencharz. "Indicator amino acid oxidation: concept and application." The Journal of nutrition 138.2 (2008): 243-246.
• Elango, Rajavel, Ronald O. Ball, and Paul B. Pencharz. "Recent advances in determining protein and amino acid requirements in humans." British Journal of Nutrition 108.S2 (2012): S22-S30.
• Gillen, Jenna B., et al. "Dietary protein intake and distribution patterns of well-trained dutch athletes." International journal of sport nutrition and exercise metabolism 27.2 (2017): 105-114.
• Hoerr, ROBERT A., et al. "Recovery of 13C in breath from NaH13CO3 infused by gut and vein: effect of feeding." American Journal of Physiology-Endocrinology And Metabolism 257.3 (1989): E426-E438.
• Kato, Hiroyuki, et al. "Protein Requirements Are Elevated in Endurance Athletes after Exercise as Determined by the Indicator Amino Acid Oxidation Method." PloS one 11.6 (2016): e0157406.
• Phillips, Stuart M., Daniel R. Moore, and Jason E. Tang. "A critical examination of dietary protein requirements, benefits, and excesses in athletes." International journal of sport nutrition and exercise metabolism 17.s1 (2007): S58-S76.
• Phillips, Stuart M. "Current Concepts and Unresolved Questions in Dietary Protein Requirements and Supplements in Adults." Frontiers in Nutrition 4 (2017).
• Thomas, D. Travis, Kelly Anne Erdman, and Louise M. Burke. "Position of the academy of nutrition and dietetics, Dietitians of Canada, and the American college of Sports Medicine: Nutrition and athletic performance." Journal of the Academy of Nutrition and Dietetics 116.3 (2016): 501-528.
• Trumbo, Paula, et al. "Dietary reference intakes for energy, carbohydrate, fiber, fat, fatty acids, cholesterol, protein and amino acids." Journal of the American Dietetic Association 102.11 (2002): 1621-1630.
• Wooding, Denise J., et al. "Increased Protein Requirements in Female Athletes after Variable-Intensity Exercise." Medicine and science in sports and exercise (2017).
• Young, Vernon R. "Nutritional balance studies: indicators of human requirements or of adaptive mechanisms?." The Journal of nutrition 116.4 (1986): 700-703.

Macros & Calories Don't Count? Better Food Choices Make Diet More Than 10x More Effective for PCOS Sufferers

Normal-weight women can have PCOS, too. Recently, Macruz et al. did DXA scans on young women with PCOS and a normal BMI and found increased truncal and leg fat compared to healthy controls in a similar age (12–39 years) and BMI range (at least 18.5 but below 25 | Macruz. 2017). More evidence that weight alone doesn't explain PCOS.

PCOS is by no means an issue only obese women suffer from. Yes, obesity is and will always be the #1 risk factor for developing the polycystic ovarian syndrome (PCOS = a condition in which a woman's levels of the sex hormones estrogen and progesterone are out of balance; this leads to the growth of ovarian cysts (benign masses on the ovaries); PCOS can cause problems with a women's menstrual cycle, fertility, cardiac function, and appearance), but eventually it seems as if both occurred in response to the same hitherto not fully elucidated triggers.

In that, it is unquestionable that a woman's diet plays a minor part in the development of PCOS. Accordingly, scientists all over the world are currently trying to determine the optimal diet for people like the 60 overweight or obese patients with PCOS who participated in a recent study from the Kashan University of Medical Science in Iran (Foroozanfard 2017).

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The study was designed to evaluate the effects of the Dietary Approaches to Stop Hypertension (DASH diet) on weight loss, anti-Müllerian hormone (AMH) and metabolic profiles in women with polycystic ovary syndrome (PCOS). To this ends, the scientists conducted a randomized controlled clinical trial among 60 overweight or obese patients with PCOS. Patients were randomly assigned to receive either a low-calorie DASH (N=30) or control diet (N=30; designed to mirror the traditional Iranian diet) for 12 weeks. What is particularly interesting is that both diets had identical macronutrient compositions: 52-55% carbohydrates, 16-18% proteins, and 30% total fats.

Table 1: Constituents of the DASH and control diets in the study; data are presented for a calorie intake of 1800 kcal/day - (b) at least 3 servings of whole grains in the DASH diet; (c) low-fat (lower than 2%) in the DASH diet; (d) 4 servings of lean meat in the DASH diet and 2 servings in the control diet (Foroozanfard 2017).

However, the DASH diet was designed to be rich in fruits, vegetables, whole grains, low-fat dairy products, and low in saturated fat, cholesterol and refined grains (cf. Table 1). Both diets were equicaloric. Physical activity was monitored and identical in both groups. To further promote the comparability between the study arms, all subjects were...

The way we eat is not just obesogenic it is also acidogenic... or is the former just a consequence of the latter? Learn more!

[...] provided with 7-day menu cycles that were individually planned using a ‘calorie count’ system. To facilitate the compliance to the diets, participants were given and instructed an exchange list. 

[...] Compliance with the consumption of diets was controlled once a week through phone interviews. The compliance was also double-monitored by the use of 3- day dietary records completed throughout the study. 

[...] To control for dietary intakes of subjects throughout the study, the dietitian was calling the participants to resolve their probable problems" (Foroozanfard 2017).

The significant difference in the study outcomes you can see in Figure 1 are thus a function of the foods and not the macronutrient composition or the total energy intake of the women.

Figure 1: Anti-Müllerian hormone and metabolic profiles at baseline and after the 12-week intervention in women with polycystic ovary syndrome; p-values indicate stat. significance of the inter-group difference (Foroozanfard 2017).

More specifically, there was almost no change in glucose management in the control, but significant benefits in the DASH group; a further increase in the hallmark features of PCOS, i.e. anti-Müllerian hormone (AMH) and the free androgen index (FAI), but a significant decrease of these indices in the DASH group; and no change and a small improvement in heart-healthy NO and inflammation, respectively, in the control, but a huge increase in NO and decrease in inflammation (MDA) in the DASH diet group.

The detailed micronutrient breakdown shows that one of the reasons of the health benefits could be an increased intake of potassium, magnesium & co - eventually, that's yet not enough to explain the benefits of making better food choices - 'cause food ≠ macros.

Improving your health by eating healthy ≠ weight loss! Despite the impressive inter-group differences in all relevant health markers that were assessed in the study, the weight loss in both groups was identical, with the subjects' BMI dropping by -1.2±0.7 and -1.6±0.5 kg/m², respectively. That goes against the mantra that the best diet was always the one that produced the greatest weight-loss. Especially in people who are battling inflammation and insulin resistance, major health improvements can be achieved without concomitant weight loss... OK, usually you would expect anthropometric changes like a reduction in waist circumference as well as body and esp. visceral fat (Ehsani 2016; Orio 2016), but, unfortunately, these parameters were not assessed in the study at hand | Comment!

References:

• Ehsani, Behnaz, et al. "A visceral adiposity index-related dietary pattern and the cardiometabolic profiles in women with polycystic ovary syndrome." Clinical Nutrition 35.5 (2016): 1181-1187.
• Foroozanfard, Fatemeh, et al. "The effects of DASH diet on weight loss, anti‐Müllerian hormone and metabolic profiles in women with polycystic ovary syndrome: a randomized clinical trial." Clinical Endocrinology (2017).
• Macruz, Carolina F., et al. "Assessment of the body composition of patients with polycystic ovary syndrome using dual‐energy X‐ray absorptiometry." International Journal of Gynecology & Obstetrics (2017).
• Orio, Francesco, et al. "Obesity, type 2 diabetes mellitus and cardiovascular disease risk: an uptodate in the management of polycystic ovary syndrome." European Journal of Obstetrics & Gynecology and Reproductive Biology 207 (2016): 214-219.

Training Volume, Intensity, and Your Libido - How Bad is It? Who Read the Study Knows: It's not Just About Cardio ... !

Both, the male and female libido are at risk by overtraining. So don't continue your daily 1h stairmaster sessions, ladies!

You may have seen this study elsewhere on Facebook before... and I have to apologize that I am late to the party, but it disappeared in the "to write about" pile on my virtual desktop and resurfaced only today when I didn't find another recent study worth writing about.

Enough of the excuses, though. After all, the SuppVersity is the place to get all the study details - including an assessment of its practical relevance and a brief glimpse at relevant related research. What? No, I bet you didn't get that in one of the reposts to the abstract on PubMed, did you? Or did you understand what a low, medium or high "total intensity" was when you read those copy and paste jobs? It's not simply the VO2max. If you thought so, you probably misunderstood the study.

Overly frequent use of intensity techniques will also put you at higher risk of libido loss:

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Now, without further delay, let's take a look at what the study actually did. To study the associations between aspects of endurance exercise training and the sexual libido in healthy men using a cross-sectional online survey was conducted. Since this is the first study of its kind, a new online survey questionnaire had to be developed. As the scientists explain, ...

"[t]he questionnaire was based upon pre-existing validated questionnaires and use to assess elements of physical characteristics, exercise traininghabits and libido of participants (n=1077). Three evidence-based categories were created for the primary outcome of total libido score and low, normal, and high response categories set. The high and normal categories were combined to form a high/normal score group and the low category formed a low score group" (Hackney 2017). 

The fact that it "was based on pre-existing validated questionnaires", namely the ADAM, the SDI-2 and the AMS questionnaire for the libido-, and the IPAQ and the Baecke questionnaire for the physical activity, i  quite important. Even though this gives it an air of authority, we have to keep in mind that questionnaires can be pretty misleading (de Yébenes Prous 2009; Rosen 2004) and eventually the one at hand is non-validated - regardless of the excellent Cronbach's alpha of 0.70 to 0.96 (Tavakol 2011) and thus a high internal consistency of the individual constituents.

Table 1: The physical and exercise training characteristics of the participants (Hackney 2017).

If we assume that there were no built-in problems with the questionnaire, and appreciate that the scientists recruitment via sports clubs, national sports organizations, university athletic departments, and sporting magazines was decently successful (N = 1077 participants filled out the questionnaires | see Table 1 for participant data | mind the age groups: 1: < 18 years = not included in analysis; 2: 18-25; 3: 26-40; 4: 41-55; 5: ≥ 56), I guess we can live pretty well with the correlations the scientists calculated between their three evidence-based categories: duration, intensity of the workouts, age and total libido score (all featuring low, normal, and high response category sets).

Update on the significance of the results for women:On Facebook, Lillian rightly asked how I could claim that women would have to avoid hours of medium-to-high intensity cardio based on a study in men. Here's a brief reminder of what I've discussed in other articles about overtraining and the (female) athlete triad. There's very good evidence that - unlike resistance training - high(er) intensity long-duration "cardio" messes with the female reproductive system and female libido (Boyden 1983; Warren 1992 & 2001). Later this week I will discuss a recent study showing that this is not the case for frequent intense resistance training, though.

The fact that all participants were men, by the way, reduces the significance of the absolute results (i.e. the hours of exercise per week and the so-called "total intensity", but the general trend(s) should be similar for women). Unlike men, however, women will yet not just lose their libido (early phase), but also notice concurrent irregularities in their menstrual cycle (later phase | see red box above).

Table 2: Part of the dataset the scientists generated - I will dissect and discuss the relevant parts below (Hackney 2017).

A problem that we cannot ignore, though, is that the high and normal categories were combined to form a high/normal score group, while the low category formed a low score group before the odds ratios (OR = how likely is it that...) - to identify what "promotes" your libido is thus not possible. What we can tell, is what will keep you in either the normal or the high libido zone and that's:

• low "chronic duration" (1-16h per week; 4-fold more likely) and medium "chronic duration" (20-40h per week; 2.5-fold more likely) compared to high "chronic duration" training (50 – 100h per week for years)
• training at low "total intensity" (0-1100 VO2max x hours per week; 6.9-fold more likely) and medium intensities (1140-2480 VO2max x hours per week; 2.8-fold more likely) compared to subjects with a high "total intensity (2500-1000 VO2max x hours per week).

So what do you make of the results? Well, the total intensity was a computed variable representative of a number of training sessions at a low, moderate, hard intensity times the hours of each per week using the well-known VO2 cutoffs of low ≤35% of VO2max, moderate ~50% of VO2max, and high ≥70% of VO2max. 

Figure 1: Odds ratio of having a normal or high libido with low and medium duration, intensity, and age (Hackney 2017).

This is an important insight, after all, it goes against the notion that "steady state cardio [even walking on the treadmill as a cool-down] is generally bad" that many people who shared this post online evoked (deliberately or not) - a HIIT session of only 10 minutes at 95% of VO2max would, after all, generate a higher "total intensity" than a steady state session of walking at 30% of your VO2max on the treadmill if both had been done five times a week in the past five years which was the median value. 

Figure 2: Intensity and duration for different types of training done five times per week for five years plotted alongside the calculated "total intensity" values and information about the risk of libido loss (Hackney 2017).

In general, however, there's no debating, the highest "total intensity" levels are probably going to be generated by the typical "fat burning workouts" I have been criticizing for years, i.e. the 45-90 minutes on the treadmill at ~70% of your VO2max, in the alleged "fat burning zone". An even higher value would be observed for the Crossfit addict doing 5x60 min workouts powering the weights up and down at 80% of his/her VO2max per week (see Figure 2 for a comparison of the different exercise modes and the corresponding "calculated intensity").

Much easier to understand than the total intensity is the "chronic duration". Being computed as the arithmetic product of the time you spend in the gym or elsewhere doing any sports it is a simple proxy of your total training volume irrespective of the form and intensity of your training that - and this is important - does not involve the number of years you've been following this approach already (for me that is a questionable methodological choice the scientists made with the previously discussed "total intensity"). The unmistakable message here is: the more you work out on a weekly basis (or the less you recover per workout hour?), the higher your risk will be.

Could something as simple as a saliva test tell you if you or your clients are overtraining? I mean, common sense would dictate that cortisol, free T and IL-6 should tell us something. Learn more in my 2016 article "Overtrained or in the Zone? Tests & Analyses of Samples of Athletes' Saliva Shall Help Determine Objective Criteria" | more

So, you better limit your weekly sports activity to 16h total!? True, that's the message the non-exercise and non-intensity specific "chronic duration" data sends. If you train more than 50hrs per week your risk of suffering from a low libido is maximal. On the other hand, people who train only 20-40h per week and 1-16h per week are 4x and 2.5x more likely to have either normal or even high libido ratings on the subjective tests that were used in the test at hand.

The "total intensity" data, on the other hand, is hard to interpret. It mixes training volume, intensity, and number of the years of sticking to this madness. So, don't remember the actual figures, but rather the following interpretation: the higher your intensity, the lower your training frequency, training time and the time you stick to this intensity withing your year-long periodization regimen should be.

Practically speaking this means: Yes, you can CrossFit or do the classic 1h cardio regimen five days a week for some time, but you should know that after months and years this is going to crush your libido, while 5x20 minutes walking or doing 5x10 minute of HIIT at 95% of your VO2max are not that likely to induce the same libido reduction | Comment!

References:

• Boyden, Thomas W., et al. "Sex steroids and endurance running in women." Fertility and sterility 39.5 (1983): 629-632.
• de Yébenes Prous, M. Jesús García, Francisco Rodríguez Salvanés, and Loreto Carmona Ortells. "Validation of questionnaires." Reumatología Clínica (English Edition) 5.4 (2009): 171-177.
• Hackney, Anthony C., et al. "Endurance Exercise Training and Male Sexual Libido." Medicine and science in sports and exercise (2017).
• Rosen, Raymond C., et al. "Male Sexual Health Questionnaire (MSHQ): scale development and psychometric validation." Urology 64.4 (2004): 777-782.
• Tavakol, Mohsen, and Reg Dennick. "Making sense of Cronbach's alpha." International journal of medical education 2 (2011): 53.
• Warren, MICHELLE P. "Clinical review 40: Amenorrhea in endurance runners." The Journal of Clinical Endocrinology & Metabolism 75.6 (1992): 1393-1397.
• Warren, M. P., and N. E. Perlroth. "The effects of intense exercise on the female reproductive system." Journal of Endocrinology 170.1 (2001): 3-11.

Gain DXA-Confirmed 3% Lean Mass Within ~12h, Glycogen Loading Does the Trick | Plus: Training on 'The Pill' & More...

The first December 2016 research update with studies that are relevant for both, women and men. I mean, who wouldn't want to get sign. more muscular in hours? I guess those who know that this is just an often overlooked measuring error.

Have you ever wondered about the accuracy of your DXA data? It's supposed to be "the gold standard", but you've learned only recently in the SuppVersity Facebook News that this is only the case if you measure at the same time of the day, identical hydration and - as a more recent study shows - even identical glycogen stores. What? Yes, that's right! You can make DXA-confirmed 3% gains in lean mass within hours. Simply by glycogen loading.

You're not interested in body fat data? Well, this is your lucky day. Today's installment of the short news will also discuss the latest study on the interaction between oral contraceptive and the adaptive response to exercise (Schaumberg. 2016).

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The Misquantified Self & More | ISSN'15 #5

BCAA, Cholos-true, Probiotics & Co | ISSN'15 #6

That's still not for you? Well, there's also the interaction between glucose, fructose and gastric emptying, which is of "urgent" (keyword: diarrhea vs. fastest glucose uptake) importance for endurance athletes (Shi. 2016).

• Diarrhea vs. fastest glucose uptake - How the glucose / fructose ratio can make all the difference (Shi. 2016) -- In their latest study, scientists investigated the effect of beverage osmolalities, carbohydrate (CHO) type and CHO concentration on gastric emptying in euhydrated subjects at rest.
  
  To this ends, the scientists measured the gastric emptying of water (W), and compared it to four glucose beverages containing either 2, 4, 6, or 8% glucose (2G, 4G, 6G, and 8G, respectively) and four sucrose (= 50% glucose + 50% fructose) beverages containing identical percentages, i.e. 2, 4, 6, or 8% of sucrose (2S, 4S, 6S, and 8S) in eight healthy subjects using the modified George double-sampling technique (Beckers. 1988).
  

  

  Figure 1: Mean gastric residual volume and gastric emptying rate in with standardized drinks with different carbohydrate sources (glucose or sucrose = 1:1 glucose : fructose) and volume (Shi. 2016).

  The scientists did not find significant differences in the gastric secretion volume among beverages across time and practically less relevant differences for the gastric residual beverage (GRBV) volume. What is interesting for you, on the other hand, is the scientists' observation that the gastric emptying rate (GER) was negatively correlated to the calories emptied (r=0.84) - and that the effect was more pronounced for glucose than for sucrose.
  
  

  

  Bad Fructose? Increased Glycogen Synthesis, Reduced Glycemia, Higher Glucose Oxidation | more

  What does that mean? Well, the answer is simple. Shi et al. provide more evidence of and a "novel" mechanism for the superiority of glucose + fructose mixes as intra- and post-workout shakes. Especially at high energy content, i.e. high levels of glucose and fructose in the drink, they are simply processed faster. Accordingly, it is not surprising that studies show benefits, not detrimental effects of adding the allegedly bad fruit sugar to a sugary intra- or post-workout shake. You can learn more about this in "Bad Fructose? Increased Glycogen Synthesis, Reduced Glycemia, Higher Glucose Oxidation" (more) and "Post-Workout Glycogen Repletion - The Role of Protein, Leucine, Phenylalanine & Insulin" (more).
  
  On the other hand, the risk of getting diarrhea may increase with each extra-gram of fructose in your intra- or post-workout beverage. The "optimal" 2:1 ratio for glycogen recompensation, I discussed in the previously cited article from 2013.
• Manipulation of Muscle Creatine and Glycogen Changes DXA Estimates of Body Composition (Bone. 2016) -- As the authors of the previously referred to study say dual x-ray absorptiometry (DXA) protocols are thought to provide a reliable measurement of body composition. In fact, however, their study shows that the accuracy will largely depend on the muscle glycogen content upon measurement (not so much on the level of creatine, though).
  
  How do they know? Well, the researchers had eighteen well-trained male cyclists (the training status is important, because the results may well differ for untrained or only recreationally active subjects) participate in a parallel group application of creatine loading (n=9) (20 g/d for 5 d loading; 3 g/d maintenance) or placebo (n=9) with crossover application of glycogen loading (12 v 6 g/kg BM/d for 48 h) as part of a larger study involving a glycogen-depleting exercise protocol. Body composition, total body water, muscle glycogen and creatine content were assessed via DXA, bioelectrical impedance spectroscopy, and standard biopsy techniques.
  

  

  Figure 2: Percent changes in leg lean and fat mass vs. baseline following glycogen depletion and creatine and glycogen loading with and without creatine (Bone. 2016).

  Their results confirm glycogen, as the primary determinant of ostensible gains. In fact, glycogen loading, both with and without creatine loading, resulted in substantial increases in estimates of lean body mass (mean +/- SD; 3.0 +/- 0.7 % and 2.0 +/- 0.9 %) and leg lean mass (3.1 +/- 1.8 %and 2.6 +/- 1.0 %) respectively. Cool? Well, the only bad news is that the DXA scan's body fat analysis will be messed up even more (+4.5% of body weight for the whole body, albeit - due to interpersonal differences - not statistically significantly) - in the end, you would thus always be told that you failed to achieve lean gains.
• Oral Contraceptive Use Dampens Physiological Adaptations to Sprint Interval Training (Schaumberg. 2016) -- Dampens? Yes, this means "the pill" will impair your fitness gains - in this case maximal oxygen uptake (VO2peak) and peak cardiac output (Qpeak), but there is good news, too... before we get to that, however, we should take a brief look at the study design.
  
  The scientists studied women taking oral contraceptives (OC | n=25) or experiencing natural regular menstrual cycles (MC; n=16) who completed an incremental exercise test to assess VO2peak, PPO, and Qpeak before, immediately after, and four weeks following 12 sessions of SIT. The SIT consisted of 10, one-minute efforts at 100-120% PPO in a 1:2 work:rest ratio.
  Now, the bad news I've already revealed is that the OC group saw a significantly reduced increase in VO2peak (OC +8.5%; MC +13.0%; p=0.010) and Qpeak (OC +4.0%; MC +16.1%; p=0.013), but the good news is...
  • the peak power output (PPO) increased to a similar extent in both groups (OC +13.1%; MC +13.8%; NS), and
  • intriguingly, the OC group showed more sustained training effects in VO2peak (OC -4.0%; MC -7.7%; p=0.010) on the follow up 12 weeks later
  Eventually, SIT did thus (i) improve peak exercise responses in all recreationally-active women, with (ii) women on OC responding significantly worse, yet (ii) more sustained (when the women seized training) than those with natural menstrual cycles.
  
  Therefore, the authors conclusion that "OC use should be verified, controlled for, and considered when interpreting physiological adaptations to exercise training in women" (Schaumberg. 2016) is obviously right - during detraining, on the other hand, it could be an advantage to be on oral contraceptives (needless to say that the adaptation conserving effects would have to be proven in a future study in which MC women would be put on OC after SIT).

Yes, I do suggest that it may be beneficial to drink these two and another two cups of coffee w/ lots of sugar after your workout - if you are an athlete, at least -- "Post-Workout Coffee Boosts Glycogen Repletion by Up to 30% and May Even Have Sign. Glucose Partitioning Effects" | more

So what's the verdict here? I guess there's no clear verdict on the headliner study. We will need a follow up to investigate whether a woman's "gains" (in this case in the conditioning department) can be conserved if she starts taking oral contraceptives during de-training. What we do know without another study, however, is that taking oral contraceptives during a training period will impair the normal physiological adaptation to sprint training.

And what about the other studies? Well, I guess if you can stomach it (and as of now, nobody complained), the previously discussed 2:1 glucose:fructose ratio is probably the "optimal" natural sugar supplement for your workout.  And if you want to measure your results, you better make sure you did not change your carb intake or had a glycogen depleting workout before doing a DXA scan | Comment!

References:

• Beckers, E. J., et al. "Determination of total gastric volume, gastric secretion and residual meal using the double sampling technique of George." Gut 29.12 (1988): 1725-1729.
• Bone, et al. "Manipulation of Muscle Creatine and Glycogen Changes DXA Estimates of Body Composition." Medicine & Science in Sports & Exercise: Post Acceptance: November 28, 2016 - doi: 10.1249/MSS.0000000000001174.
• Schaumberg, et al. "Oral Contraceptive Use Dampens Physiological Adaptations to Sprint Interval Training." Medicine & Science in Sports & Exercise: Post Acceptance: November 28, 2016 - doi: 10.1249/MSS.0000000000001171.
• Shi et al. "Effect of Different Osmolalities, CHO Types, and [CHO] on Gastric Emptying in Humans." Medicine & Science in Sports & Exercise: Post Acceptance: November 28, 2016 -doi: 10.1249/MSS.0000000000001176.

HIIT Sheds 25% Intra-Bellyfat in 32 Workouts - Despite T2DM & W/Out Dieting! Plus: Always 'Add Weights' When Dieting

High-intensity interval training (HIIT) sheds significantly more belly fat over (-10% vs. 0%) and under (-25% vs. +10%) female abs than isocaloric medium intensity steady state exercise aka MICT.

Losing 25% of visceral fat without dieting and with only two workouts per week (16 weeks x 2 workouts = 32 workouts total)? That sounds like straight from a 'spam ad' on Facebook, right? Well, it is based on scientific evidence, though... evidence from a study in Diabetes & Metabolism that tested the effects of a very manageable high-intensity interval training regimen (2 x 20 min per week) on abdominal fat mass in postmenopausal women with type 2 diabetes (Maillard. 2016).c

Ok, I have to admit that's different from both, (a) the athletes in the second study that made it into today's SuppVersity short news (the one about maximal fat oxidation) and (b) the average SuppVersity readers, but knowing the exact protocol, which is different from much (if not everything) you may have seen so far, alone, should be reason enough to read the rest of today's SuppVersity Short News (all short news | make sure to scroll down and click on "older news" at the bottom).

Read more about exercise-related studies at the SuppVersity

Tri- or Multi-Set Training for Body Recomp.?

Aug '15 Ex.Res. Upd.: Nitrate, Glycogen, and ...

Pre-Exhaustion Exhausts Your Growth Potential

Full ROM ➯ Full Gains - Form Counts!

Body Pump, Cardio & Exercise Expenditure

Study Indicates Cut the Volume Make the Gains!

The former is particularly true since the scientists tested another, albeit non-HIIT training regimen, too, one that resembles what the seventeen women (69 ± 1 years; BMI: 31 ± 1 kg/m²) who participated in the study would probably have done if they had not been randomly assigned to the classic, but useless ...

• medium intensity cycling training (MICT) - 40 min at 55–60% of their individual HRR as calculated by (estimated HRmax − HRrest) × 0.55 (or 60%, respectively) + HRrest - instead of the previously hinted at
• high-intensity interval training (likewise cycling) HIIT program - 60 × 8 s at 77–85% HRmax, 12 s of active recovery (at 20–30 rpm) - that yielded impressive results

for only for 16 weeks with two isocaloric (= EEs per session did not differ between the two modalities (262 ± 58 kcal with HIIT and 240 ± 58 kcal with MICT; this is a difference to many previous studies, where, oftentimes, the steady state group burned more energy during their workouts) workouts per week. As promised in the headline, it did thus take as little as 32 workouts for the results to become measurable (via dual-energy X-ray absorptiometry) and visible - and that in spite of the lack of reductions in energy intake in both groups:

"Women were asked to maintain their normal eating habits during the 16-week study period. At baseline and at week 16 of training, each participant provided a 7-day food-intake diary, which was evaluated by a dietitian using nutrition analysis software (Nutrilog®, Marans, France)" (Maillard. 2016).

In addition, the subjects were "asked to maintain their normal levels of physical activity during the study period" (Maillard. 2016).

Whatever you do: If you want to lose weight - exercise! It's not just the study at hand that underlines how powerful (especially) HIIT exercise is when it comes to fat, not weight loss. Another recently published study by Edward P. Weiss et al. adds to the already convincing evidence that exercise protects you from the decreases in lean mass and reductions of VO2max that occur with deficits as low as only 20% (Weiss. 2016). In their study, Weiss et al. had observed that the ~2% (p=0.003) whole body and ~4% (p<0.0001) lower body lean mass loss that occurred during 15-18 weeks of dieting at 80% of the maintenance intake was reduced to non-significant 1% (p=0.44) and only just significant <2% (p=0.05) lower body lean mass loss while the ~6% decrease in aerobic exercise capacity was totally blunted with only 4.4+/-0.5 hr/wk of walking, jogging, cycling or more intense functional physical activities, such as yard work - needless to say that replacing that by a fast-paced strength training regimen (explicitly precluded in Weiss et al.) or concomitant strength + cardio training may have reduced the lean mass losses to zero, as well. 

Now, I have to admit I haven't told about the importance of a small word in the headline yet. The word is "intra-" and points away from belly fat in general and towards the "intra-belly" visceral fat with it's unhealthy effect on blood lipids and glucose levels.

Figure 1: Body composition changes [based on dual-energy X-ray absorptiometry (DEXA) imaging] between baseline and end of the 16-week exercise program with MICT (n = 8) and HIIT (n = 8). Data are means ± SEM. MICT: moderate-
intensity continuous training; HIIT: high-intensity interval training; FFM: fat-free mass; FM: fat mass; delta
change (%) = [(16 weeks − baseline/baseline) × 100]. *P ≤ 0.05 (MICT vs. HIIT groups | Maillard. 2016).

With ~10%, though, even the total belly fat loss (visceral and subcutaneous) is remarkable. After all, there was (a) no dieting involved and (b) not even the slightest fat loss in the classic cardio group!

In January 2015 I wrote an article with the title "5 Reasons Why 50%+ of Your 'Cardio' Should Be HIIT". Now in 2016 the science is still valid | more

Beware of condemning MICT training! While you have read about the benefits (listed here) of doing HIIT before, there are also good sides of LISS and MICT. This is why I would like to remind you / prepare you for / a fact I highlight / will highlight in the bottom line, too: the study at hand shows nothing but the fact that in this subject group and (solely) for the purpose of losing visceral fat in the absence of dieting and, more importantly, in the absence of lifting weight, HIIT appears to be (albeit vastly) superior to an isocaloric bout (=you spend the same amount of energy training intensely and with intervals) ofsp steady state cardio (MICT).

If you lifted weight, for example, doing two types of exercise that tax the sympathetic nervous system may tax the CNS and produce results that are worse or not better than steady state cardio. Alternatively, if you lifted the calorie limit on the MICT, on the other hand, you may see (just as many previous studies did) that the extra calories burnt during MICT will help you lose more weight and often also more body fat. It's all about specificity and finding out what works for you!

A group of which the data in Figure 1 tells you that the subjects who have been randomly assigned to do "their cardio" (MICT) even got 10.5±9.7 % fatter (viscerally, as measured by CT scans) over the course the 16-week study.

Figure 2: Lipid, fasting glucose and HbA1c changes from baseline to week 16 with moderate-intensity continuous training (MICT; n = 8) and high-intensity interval training (HIIT; n = 8 | Maillard. 2016).

Against that background, the scientists' observation that the 'bad' plasma triglyceride levels were higher with HIIT (group effect, P ≤ 0.05), while "overall, HbA1c and TC-to-HDL ratio both decreased after the intervention (time effect, P ≤ 0.05)" without significant inter-group differences. That sounds odd. As odd as the increase in fasting glucose. So what? Well, what is important, is that

"[...] the total cholesterol (TC) reduction was positively correlated with total visceral FM loss (r = 0.39; P ≤ 0.05) and HbA1c change was positively associated with the decrease in abdominal FM (r = 0.29; P ≤ 0.05)" (Maillard. 2016).

which points to an overall long-term benefit of HIIT on both, lipid and glucose metabolism. All that after 16 weeks, over which the scientists' nutrition and activity data confirm that the subjects did not - as they were advised - change their levels of physical activity (IPAQ score) or total energy (kcal) intake and macronutrient consumption (distribution and total amount).

'Inspiratory Muscle Training, HIIT or RT for Your Kids? Cold Water Immersion & Altitude Training - Who Benefits, When?' Learn about the latest exercise science on HIIT and more

Shouldn't the extreme visceral fat loss... trigger more significant improvements in 'bad' blood lipids (LDL) and glucose metabolism and by no means elevate triglycerides?

The latter is a valid question, but one you wouldn't ask if you were familiar with the effects of intense glycolytic training (HIIT, sprints, weights, etc.) on triglyceride levels, which are increased, because (a) HIIT & co will increase the amount of fat that is released from the fat cells (esp. after the workouts), while they (b) burn less fat than "classic cardio" during the workouts. To consider that "health-damaging" would thus be unwarranted.

And while I cannot explain, though, is why we don't see more significant improvements in the blood lipid composition of the HIIT group, I do know that (a) this is likewise a result, scientists have previously observed in scientific studies and that (b), and more importantly, none of the inter-group differences (including the nasty increase in LDL) was statistically significant (in fact, the p - values were all p > 0.5 [no typo], when p < 0.05 would signify statistical significance).

Overall, the studies main and only message is thus exactly what you've read in the headline: You can lose highly significant and significantly more belly fat (not total body fat, where both groups lost the same 1-2% of their total fat mass | another potential explanation for the lack of sign. differences as far as health benefits are concerned) if you invest 2x20 minutes into HIIT training per week compared to "classic steady state cardio" aka MICT. That's the message of the study - a message I would like to complement with (a) the advice from the light blue box, i.e. "Whenever you're tryin' to lose weight, do resistance training, too. Your muscles will thank you!", and (b) the reminder that this is a single study with an important limiter that is not always valid in the real world, i.e. identical energy expenditure in both arms of the study, if that's not guaranteed (and usually people burn more during "cardio" than during HIIT (including its aftermath)) the HIIT advantage you see in this study may easily melt away | Comment!

References:

• Maillard, F., et al. "High-intensity interval training reduces abdominal fat mass in postmenopausal women with type 2 diabetes." Diabetes & Metabolism (2016).
• Weiss, P et al. "Effects of Weight Loss on Lean Mass, Strength, Bone, and Aerobic Capacity." Medicine & Science in Sports & Exercise: Post Acceptance: August 30, 2016 [ahead of print]. doi: 10.1249/MSS.0000000000001074.