Sunday, August 3, 2014

Female Athletes' Body Composition Suffers From Chronic Energy Deficits: Effects of Energy, Protein, CHO Intake, Timing & Distribution in Gymnasts & Volleyball Players

Even female volleyball players are wo- men - no wonder they tend to undereat ;)
Usually we are learning about what makes us fat by looking at those who are fat. Studies on athletes like gymnasts and volleyball players, and what influences their body composition, on the other hand, are scarce. Reason enough for me to take a closer look at two thesis by graduates from the Georgia State University who analyzed the relationship between moderate, within day protein intake and energy balance on body composition of collegiate sand volleyball players (Richardson. 2014) and the relationship between daily protein distribution and body composition in elite gymnasts (Paszkiewicz. 2014) - research that could be relevant for both, men and women.

I guess many of you will remember that I've written about gymnasts before - in July 2013, to be precise. In said article with the telling title "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" (read more) I analyzed the negative effects of "starvation" on body composition to highlight that simply not eating or eating like a bird is not going to give you the Shape cover model body, many girls are looking for.
You can learn more about improving your body composition at the SuppVersity

Dieting Makes Gymnasts Fat!

Minimal Carb Reduction, Max. Results?
HIT Circuit + Plyos for Glucose Management

How Much Carbs Before Fat is Unhealthy?

5 Tips to Improve & Maintain Insulin Sensitivity

Carbohydrate Shortage in Paleo Land
In spite of the fact that the titles of the two studies and hand and the previously cited study by Deutz differ, the objectives are not very different:
  • "The  purpose  of  this  study  was  to  simultaneously  assess  energy  balance  and
    protein  intake  to  determine  if  these  factors  are  associated  with  body  composition  in  a
    population of collegiate sand volleyball players." (Richardson. 2014)
  • "The objective of this study was to determine the relationship between hourly EB and protein intake with body composition" (Paszkiewicz. 2014)
If you look at the exact ways the authors phrase it, it does yet become obvious that Richardson (2014) puts a greater emphasis on the amount of protein, while Paszkiewicz is, just like Deutz back in the day, very interested in the hourly energy balance (EB) and thus the time the subjects remain in a positive / negative energy balance.

Apropos subjects! In the gymnasts who participated in Paszkiewicz' study were elite and highly
competitive athletes from several training gyms across the country. The information on their daily food intakes was elucidated by the means of secondary analyses that were performed on previously collected three-day food diaries and the interactions with body composition were calculated by comparing intakes and anthropometric measures (made with DEXA).
Table 1: 
Subject
 Characteristics of the Gymnasts 
 (N=
40; Paszkiewicz. 2014)

Table 1 provides an overview of the subject characteristics. If you take a closer look, you will see that there is a pretty broad range from hardly any muscle to pretty muscular and from ripped to the shreds to average body fat.
There is one general problem with the "energy balances" in both studies! Being based on the standard equations, they are - at beast - a proximate of what the women really need. For the gymnast study, the difference between energy in and out is yet large enough to safely assume, they were really starving itself. For the volleyball study, I wouldn't be so sure - specifically in view of the fact that the body has its means of sparing energy, when it's chronically getting less than it would need - the corresponding changes in thyroid & other hormones have yet not been studied by either Paszkiewicz or Richardson.
If we take a closer look at the correlations Paszkiewicz found, some of you may be surprised to see that the relative carbohydrate intake (as percent of macronutrients) was not just positively associated with higher lean mass (see Figure 1), but also negatively with fat mass (R = -0.043).
Figure 1: Minimal, maximal and average energy balance in the gymnasts (left); positive correlates and correlation coefficients R of lean mass in 40 elite competitive female gymnasts (Paszkiewicz. 2014)
The amount of protein the gymnasts ate, however, was not significantly associated with increase lean mass. In fact, when we compare two groups, i.e. those with a high and those with a low protein intake, statistics inform us that "the higher protein group ha[s] a statistically significant lower FFM [fat free masss]" (Paszkiewicz. 2014).

Are high(er) protein intakes bad for gymnasts or, what?

Personally I suspect that this is due to a correlation between high(er) protein intakes, lower cabohydrate intakes (R = -0.595) and, most importantly, a reduced overall energy intake, which is associated with lower lean body mass and (listen up, ladies!), just as it has been reported by Deutz et al. previously, increased body fat % (reread the corresponding article from July 2013).

But why don't we have a look at the other study? Beach volleyball players are regarded as the epitome of health and sexappeal, so things could easily look different for them compared to the "frail" gymnasts, right? With a mean body fat % of 18% and a standard deviation ±7% the twelve women from the GSU sand volleyball team who participated in Richardson's study have a much healthier body fat percentage than the average, let alone extreme gymnast in the previously discussed study (we got to be careful here, because the BF% in the Richardson study was measured by body impedance and could thus easily be 5% off).
Reduced bone mineral density is a surprising negative side effect to highe(er) protein intakes in the study at hand. According to Paszkiewicz "[h]igher protein consumption was significantly associated with lower bone mineral density(BMD)in the gymnasts at the arms (r= -0.535; p < 0.001), legs (r= 0.0523; p = 0.001), trunk(r= -0.517; p = 0.001), spine (r= -0.472; p = 0.002), and pelvis (r= -0.539; p < 0.001)." (Paszkiewicz. 2014) Previous studies have yet shown that a high protein intake, in the absence of a continuous energy deficit as it was observed in the study at hand, will not lead to brittle bones. And in an energy sufficient scenario it's rather the lack of little veggies and fruits, as well as other alkalizing foods, than the amount of protein that's to blame for previously observed correlations (Heaney. 2008).
With a mean BMI of 22 kg/m², all female participants of the study were normalweight and consumed a diet with >1.94g protein per body weight (mean intake 132 ±52 g per day). An amount of protein most of the ladies spread across the day with a mean 26.06 (±10.51) g being consumed on every eating opportunity. That's not yet the "SuppVersity suggested" amount of 30g of protein per meal, but it's getting close, yet with an uneven distribution from AM to PM:
  • 30g from 6-12 AM,
  • 63g from noon to six PM,
  • another 39g in the evening
In contrast to many average Janes and Joes, the study participants consumed almost half of the mean protein intake during mid-day, while their protein intake from 6 pm to midnight amounted to only 24(±23) % of their total daily protein consumption. Still, Richardson is right to point out that
"[...] protein intake distribution was skewed, on average, toward the latter half of  the  day  with  approximately  19%  of  protein  consumed  in  the  morning  and  34% consumed  in  the  evening." (Richardson. 2014)
Much to my surprise, the ladies in the beach volley ball team were similarly anorexic as their peers in the gymnast group. With -404  (±385) kcal/day the average energy balance was clearly negative; and even if the standard deviations indicate that this was not the case for all of the ladies, the athletes spent 17 hours, on average, in a catabolic energy balance state (< 0 kcal) on a daily basis.

A high relative protein intake was not associated with better body composition!

Interestingly, though, no significant correlation was found between energy balance per gram of protein consumption and body composition.
Table 2: Spearman’s Correlations: Six Zone Protein Intake and Body Composition (N=12; Richardson. 2014); FFM – fat free mass: FFM to Ht ratio – amount of FFM per cm of height; eating Opportunities – number of times athlete consumed calories; 24 Hour EB – net kcal at the end of the day (energy consumed less energy expended)
The picture that emerges from a regression analyses with respect to the relation of energy balance and protein variables is in fact dubious (see Table 2). The only significant correlations (bold) are a positive correlation between fat free mass (FFM) and protein intake late, and a negative correlation between fat free mass and protein intake early in the AM. A similarly confusing, yet at no time significant association arises for the fat mass, which correlates negatively (albeit with p = 0.678 statistically non-significantly) with the number of meals with a protein content of 25g or more.
PWO glyocgen repletion done right may also help maintain normal leptin levels | learn more
Bottom line: If there is any clear take home message from the study at hand, it would be that chronically low energy intakes below the maintenance, or as Paszkiewicz calls it the "optimal energy intake" appears to have a negative impact not just on the body composition of young female athletes, but also impairs / nullifies the beneficial effects high(er) protein intakes have on the changes in body composition in short term (vs. chronic!) phases of energy deficiency.

Whether and to which extend these changes are related to reductions in leptin expression and/or other hormonal defects that occur in response to the (sometimes life-)long starvation diets many women follow would have to be elucidated in future studies.

The association between higher CHO intakes and better body composition Paszkiewicz observed in her study, on the other hand, appears to support the often heard hypothesis that the already established links between carbohydrates and high energy refeeds after energy restriction, on the one hand, and a restoration of rock bottom leptin levels (Romon,. 1999; Wisse. 1999), on the other hand, would warrant the use of high(er) carb refeeds on a diet - specifically if it's low in carbohydrates.
References:
  • Heaney, Robert P., and Donald K. Layman. "Amount and type of protein influences bone health." The American journal of clinical nutrition 87.5 (2008): 1567S-1570S. 
  • Paszkiewicz, Julie A. "Relationship Between Daily Protein Distribution and Body Composition in Elite Gymnasts." (2014).
  • Richardson, Barbara B. "The Relationship between Moderate, Within Day Protein Intake and Energy Balance on Body Composition of Collegiate Sand Volleyball Players." (2014).
  • Romon, M., et al. "Leptin response to carbohydrate or fat meal and association with subsequent satiety and energy intake." American Journal of Physiology-Endocrinology And Metabolism 277.5 (1999): E855-E861. 
  • Wisse, Brent E., et al. "Effect of prolonged moderate and severe energy restriction and refeeding on plasma leptin concentrations in obese women." The American journal of clinical nutrition 70.3 (1999): 321-330.