Increasing Adolescent Obesity Among Girls: How School Stress is the New Scapegoat When the Skinny Fat Phenomenon and Twinkie Diets Really are to Blame.

Image 1: Was it school stress that cost Michelle Obama her famous "guns" (=muscular upper arms)? Probably not - and despite contrary conclusions in the study at hand, I doubt that it is school stress that leaves our daughters fat, but undermuscled. What do you say?

According to the results of a recent evaluation of the data from the European HELENA trial, school, or rather the stress your children are exposed to within the educational system, may be one of the reasons for the increasing number of obese adolescents (age 12-18 years) - at least if we trust the statistical finesse of Tineke De Vriendt, Els Clays and 10 other scientists who recently published a paper on European adolescents’ level of perceived stress and its relationship with body adiposity in the European Journal of Public Health (DeVriendt. 2011). The study was part of the Healthy Lifestyle in Europe by Nutrition in Adolescence cross-sectional study (HELENA-CSS), the aim of which is to obtain "reliable and comparable data from a selected cohort of European adolescents concerning a broad variety of parameters related to nutrition, health, physical activity and fitness", or in other words, to provide the epidemiological back-bone for the formulation of more or less mainstream hypotheses on "why we are getting sick and obese"... be that as it may, with a sample size that allows for a confidence level of 95% and <0.3 error and 3865 adolescents from more than 10 European cities, the data from the HELENA study is probably the best we can get at the moment and thus you may nonetheless be interested to hear that ...

School-related stress was demonstrated to be a main source of stress in European adolescents, [...and] in adolescent girls (but not in boys), a positive association was observed between their level of perceived stress and measures of general and abdominal obesity.

If you have a closer look at the stress data, expressed on a 6-scale Likert scale from 1 = ‘Not at all stressful’ over  2 = ‘A little stressful’, 3 = ‘Moderately stressful’, 4 = ‘Quite stressful’ to 5 = ‘Very
stressful’ (with 6 indicating ‘Is irrelevant to me’), you will notice that school and the closely related fear of an "uncertain future" are in fact the major stressors in the life of our adolescent children (and you may safely assume that the results won't be very different in the US).

Figure 1: Overview of perceived stressors; values expressed on a Likert-scale from 1 to 5 (data adapted from DeVriendt. 2011)

In that, it is yet interesting to observe that none of the stressors is on average perceived as "quite stressful" or even "very stressful". It is also noteworthy that on 5 out of 10 scales and on the summary scores girls experienced more stress than boys. In view of the scientists previously cited conclusion (of which I do not have to tell you that it is based on one of those sophisticated *cough* statistical models) that only "in adolescent girls (but not in boys), a positive association was observed between their level of perceived stress and measures of general and abdominal obesity", it may thus surprise you to hear that the obesity rate among boys is more than 2x higher than among adolescent girls (cf. figure 2). So how is that?

Figure 2: Body adiposity characteristic of study sample (n=1121) of adolescents from the HELENA trial (data adapted from DeVriendt. 2011)

Well, we all know that even with a perfectly "normal" BMI, you can easily be "skinny fat". A phenomenon of which I feel that it is becoming the norm, not the exception, among adolescent girls, who - after their nth an-apple-a-day diets have lost nothing but muscle and thus have a very high body-fat percentage with a low overall body-weight.

This hypothesis would be confirmed by the regression coefficients of the statistical models from the study, according to which the association of perceived stress with the body fat level of the girls is 7x higher than the association of perceived stress and BMI, which is something that should you make reconsider, whether

1. body weight and BMI is an important biological measure, at all,
2. the real "obesity" rate, including skinny fats, among girls is not way higher than the 1.9% reported in the study would suggest, and
3. in how far school-stress, despite being the "major stressor" in this survey and not a misguided beauty-ideal is to blame for the increasingly unbalanced ratio of lean to fat mass in adolescent girls

The importance of the latter, i.e. a questionably beauty-ideal, in the etiology of (and this would be ironic if it was not so unfortunate) diet-induced obesity could also explain that the pubertal stage the girls were in and not stress or their diet had the greatest "explanatory value" (remember: we are talking of associations here) in regard of their body fat levels (cf. figure 3).

Image 2: Low self-esteem and false beauty-ideals pave the way into disordered eating and life-long misery. Something you want to spare your daughter and son, don't you?

Did you know that according to a 2000 national survey 45% of the girls, but only 20% of the boys from 5th to 12th grade reported to have tried one or more diets at some point in the past (Neumark-Sztainer)? And would you have guessed that 17% did even consider their own eating behavior as already "distorted"? Needless to say that both of these factors showed a high correlation with overweight status, low self-esteem, depression, suicidal ideation, and substance use; and certainly reason enough for you to help our children (girls and boys) not to fall victim to ill-advised beauty-ideals and false dietary recommendations.

And from the fact that the same variable had 7x less predictive value in boys, who obviously do not want to be skinny fat and refrain from Twinkie-style low calorie, low fat dieting, we can with some caution (due to hormonal effects on fat accumulation) conclude that it is not just a time factor, meaning that the older girls have more time to accumulate body fat...

Figure 3: Regression coefficients (=associative strength*100) of stress or pubertal stage with body-fat percentage in adolescent boys and girls from the HELENA trial - mind the logarithmic scaling! (data adapted from DeVriendt. 2011)

Now, what can you do about that? Well, without even knowing you probably have already done something! Assuming that you (just like every other reader of the SuppVersity ;-) are of above-average intelligence, your education has already provided your daughter, but not your son, with a better chance of staying lean than her peers from less educated parents (~80x higher explanatory value than stress!). All that is left now to make absolutely fat-proof, is to tell her that strong, not skinny fat is the new beautiful ;-)

Do Chronic Energy Deficits Make Athletes Fat? The Longer & More Severe You Starve, the Fatter You Are. Irrespective of What the Calories-in-VS-Calories-Out Formula May Say

This is not an "anti-gymanstics" or "anti-runners" article, this is an anti-ruin-your-life-post for the average female and male gymrat.

Maybe you've read about the results Deutz, Bernardot, Martin and Cody published in their 1999 paper on the "Relationship between energy deficits and body composition in elite female gymnasts and runners"... in fact, it may be possible that I already mentioned it in the "Athletes Triad Series" (read more), but even if I did, the fact that I get messages like "I eat 1,100kcal/day and still gain, not lose fat" or "my girlfriend eats 900kcal/day and maintains that this is normal", tells me it does not matter if I mention one or two of the figures the authors compiled in this unfortunately highly "under-cited" paper (only 72 citations are referencing this article) twice.

If that makes just one of the victims of their own ambition rethink what he or she is doing, it was well worth... wouldn't you agree?

Can the elite be wrong?

Usually you would assume that elite athletes are doing everything right, they are the epitome of our modern understanding of "health". As a SuppVersity reader you are yet well aware that there is a disconnect between optimal health and performance and with the latter being in part dependent on having a certain look as it is the case for bodybuilding, figure competitions and the like this disconnect can be so huge that being successful may eventually require a non-genetically gifted athlete to sacrifice his or her health on the altar of a misinterpretation of "physical culture".

That being said there is a way more traditional and, contrary to bodybuilding, officially Olympic sport where similar rules apply: Gymnastics! Especially among the female competitors the paradigm still is - the thinner the better. And to make things even worse, in this case "thin" actually means "thin" as in "being able to hide behind a straw". Now, this is obviously not the case in any of the aforementioned disciplines and yet they claim way more victims of life-long dieting than those sports, where "being thin" is actually part of the game - and what's almost sarcastic, the tortures some professional and many hobby athletes subject themselves to are not even rewarded.

You will have to take the following figures with two grains of skepticism! One for the scientifically established bias due to under-reporting in female gymnasts (Jonnalagadda. 2000), and the other one for the discrepancy between factual and calculated energy expenditures, which is, due to the negative feedback chronic dieting exerts on the total energy expenditure, much narrower than the formulas suggest. And another thing, remember that we are talking about body-fat % not total body fat masses here!

Against that background you will probably not be surprised to hear that the vast majority of the elate female artistic (N=32) and rhythmic (N=11) gymnasts in the study at hand is consuming 1,002kcal less than they would actually need to satisfy their caloric demands.

Figure 1: Comparison of within-day energy balance in the four groups of elite athletes (left); largest energy deficit per hour and average 24h energy deficit in all athletes, gymnasts and runners (Deutz. 2000).

If you take a closer look at the data in figure 1 you will yet realize that the average medium- and long-distance runner is not much better off. Now, whether the latter is a necessary prerequisite to make it to the top or simply a result of being unable (for physical or psychological reasons) to compensate for the training induced increase in energy expenditure, is beyond the scope of this post and essentially irrelevant to the statistically highly relevant acorrelation between between energy balance and body fatness, I've plotted for you in figure 2.

Figure 2: Relationships (Pearson correlations) between energy balance factors and body fat percentage in all athletes, gymnasts, and runners (Deutz. 2000)

I hope that these results do not come as a surprise for the vast majority of those for whom this is not the first visit to the SuppVersity. After all, I have been trying my very best for years (hard to believe I am doing this "chronically" ;-) to scare you away from the chronic and towards the cyclic calorie reduction as a means to cut body fat and maintain muscle mass (note: with the relatively small study size not all effects reached statistical significance; for the parameters pertaining to the "energy out vs. energy in"-calculations the average dieter is so fond of, this was yet particularly noteworthy).

In athletes chronic "dieting" results in an increase in body fat percentage

The message is simple and so is the underlying mechanism. The chronic provision of an insufficient amount of energy leads to a metabolic downregulation that goes hand in hand with an increased disposition to store and a decreased disposition to let go of body fat.

Another note: This is not an anti-intermittent fasting article either. If you do IF to cut weight you will have an overall negative energy balance, just like on every other diet, but if you are doing it for life (for whatever reason), you should be meeting your daily energy demands. This means you would have a much higher energy surplus on the other hours - in essence the data simply don't apply to someone who is doing intermittent fasting on a maintenance diet.

The concomitant exercise induced physical stress lulls your body to believe that you are amidst a starvation period, where building muscle and/or maintaining more muscle than is absolutely necessary to sustain the regular exercise routines is a no go and each and every energy unit that that is not necessary to keep you from passing out will get stored to cover those hours with a per hour deficit of 750kcal (which is the average maximal deficit per hour in the rhythmic gymnast group).

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Bottom line: Don't get fooled by the "Don't worry. That's not you, starve yourself! It's good for you - don't you feel it?" the little gal or guy in your shoulder is now whispering into your ear. The rule "chronic starvation = increase in body fat percentage" applies to male and female athletes, gymnasts, runners, sprinters, cyclists, fitness junkies, bodybuilders, footballers, ... and across a wide range of energy deficits.

You don't have to eat burgers and French fries all day, to meet your energy requirements. Living on chicken breast & broccoli for the rest of your life is neither necessary nor conducive to your goals, and that's even true for such profane goals as "staying lean"! And by the way - how much do you need (learn more)?

So say good buy to the little guy with the hunger high and use your brains and acknowledge to yourself: "I am a junky. A starvation junky!"  You are not? Well then check this out:

Addiction is a persistent, compulsive dependence on a behavior or substance. [...] Addiction has been extended [...] to include mood-altering behaviors or activities." (Livingston. 2008; my emphases)

And the main criteria for being addicted are a loss of willpower, fear of harmful consequences, an unmanageable lifestyle, tolerance or escalation of use and withdrawal symptoms upon quitting. Well if all that is not you and you. Stop working out like mad and return to eating normal without going crazy whenever you feel satiated, now!

References:

• Deutz RC, Benardot D, Martin DE, Cody MM. Relationship between energy deficits and body composition in elite female gymnasts and runners. Med Sci Sports Exerc. 2000 Mar;32(3):659-68. 
• Jonnalagadda SS, Benardot D, Dill MN. Assessment of under-reporting of energy intake by elite female gymnast. Int J Sport Nutr Exerc Metab. 2000 Sep;10(3):315-25.
• Livingstone, C. "addiction." Dictionary of Sport and Exercise Science and Medicine. 2008. Elsevier Limited 14 Jul. 2013 http://medical-dictionary.thefreedictionary.com/addiction