Saturday, June 16, 2012

Women Have a Much Harder Time Losing Body Fat Than Men, But Both Benefit From Doubling Their Protein Intake!

Image 1: Looks good, tastes good, is good - and contrary to zinc, ingesting 2x the RDA will help you lose body fat, instead of setting you up for insulin resistance.
Enough of useless (ALA, zinc) and useful (glutamin) supplements for at least 24h! Let's get back to what really counts: Training? No, not today,.. the other thing! The one, which is actually to be supplemented - your diet! Believe it or not - even after all those years, I am finding time and again that the food you put into your mouth has much more pronounced effects on the ways you look feel and perform than any of the countless useless and useful supplements. Accordingly and in response to the futile notion of "calories in vs. calories out" and the bomb-calorimeter representation of the human metabolism as a simple furnace, the past couple of years have seen an increasing public and (as of late) scientific interest in the effects varying macronutrient compositions will have on your ability to shed weight and, more importantly, to keep it off in the long run.

Submitted on December 30, 2011 and published in the latest issue of the Journal of Nutrition & Metabolism (9:55) the results of a "randomized clinical weight loss trial" comparing more or less isocaloric (-500kcal/day) weight loss regimen in 130 (58 male, 72 female) overweight middle-aged (40-56) subjects (BMI  =  32.5  ±  0.5 kg/m²) provide further insights into the real-world effects of  prescribed minimal protein intake levels on the outcomes of a 4 months weight loss and 8 months weight maintenance intervention (Evans. 2012).

RDA = 0.8g/bw vs. 2x RDA = 1.6g/bw protein - Round 1: Education & Adherence

In many of the previous posts on this issue (e.g. "High Carb vs. High Fat for Obese Type II Diabetics and What Really Happens, When Science Meets Real Life"), adherence or even an appropriate awareness of what "high protein" actually means turned out to be one of the main culprits as far as the significance of respective data is concerned (Krebs. 2012). In this respect, the subjects in the study by Evans et al. who were supported by a pretty extensive educational and support program that included
  • the provision of electronic food scales and instruction on how to weigh and record food servings at all meals (logs were monitored for compliance on a weekly base!)
  • a specific diet program with detailed instructions from a research dietitian including the menus, food substitutions and portion sizes
  • an obligatory weekly 1 h meeting at the weight management research facility, where they received dietary counseling, had the ability to pose questions and instructions referring to the minimum of 30 min of walking 5 d/wk
constitute a positive exception from the average "study participant" who receives a handout with instructions and a clammy handshake for his/her willingness to step on the scale twice within a given time-frame.
Figure 1: Energy intake (total) from different macronutrients (left) and relative reduction compared to basesline in the 4-month weight loss and the subsequent 12 months "maintenance" period (based on Evans. 2012)
Based on the activity logs, the average amount of exercise was less than 100min/wk and not different between the two treatment groups. As far as the drop outs are concerned, there was yet a trend for lower drop out rates of the male participants in the protein compared to the carbohydrate group (9/28 vs. 18/30). 
Figure 2: Adherence to the prescribed macronutrient ratios was similarly "good" for men and women in both the high carbohydrate and high protein arm of the study (based on Evans. 2012)
The overall adherence to the prescribed nutrient ratios, i.e. 15% protein, 55% carbohydrates and 30% fat in the high carbohydrate and 30% protein, 40% carbohydrates and 30% fat in the high protein group was similarly good (the deviations were smaller than one standard deviation) among both men and women; and still, the net results of the study appear somewhat disappointing - at least if you make the all too common mistake of judging the outcome of an already intrinsically mislabeled "weight loss" intervention solely by the figures on your scale, which were, for the subjects in the study at hand, identical for both groups (PRO:-10.7  ±  6.8 %, CARB:-10.1  ±  6.2 %, expressed relative to body weight at baseline).

Feminists beware! Life is not fair...

A closer analysis of the data does yet reveal that despite an overall greater reduction in calorie intake in the high protein group (-31% vs. -22% in the weight loss phase and -27% vs. -16% in the maintenance phase) and slightly but statistically non-significantly greater body fat loss in the male participants on the high carbohydrate diet at the end of the maintenance phase, the "net" effect on the lean to fat mass ratio in men and women speaks in favor of increased protein intakes during phases of reduced energy intake.
Figure 1: It is obvious that compared to baseline the loss in body fat (expressed relative to baseline, left) was significantly more pronounced in the male compared to the female participants; the favorable effects of the high(er) protein diet on the lean to fat mass ratio (4% and 6% greater improvements) is yet of even greater importance for the ladies.
There is yet no denying that middle-aged women are - irrespective of their diets - having a substantially harder time losing body fat than men of the same age. In view of the fact that this is at least partly mediated by their significantly lower lean body mass to fat mass ratio (1.3 in women vs. 2.2 in men), the aforementioned protein sparing effects of "high" protein diets are of even greater importance for female dieters than for their male peers (cf. figure 3, right) - unfortunately, even the latter rarely rarely spare a thought about that, when their short-sighted and often likewise overweight Dr. tells them "you got to lose weight, if you want to see your grand children graduate, buddy!"

... and if you want sexual equality you got to lift weight and eat your meat ;-)

Against that background the results of the recently published exercise-only trial by Washburn et al. come to mind (cf. "Strength Training Ain't For Women -  Really!?" and Washburn. 2012). In the study at hand, The absence of at least a minimalist strength training regimen, as it was employed in the Washburn study, could in fact be one of the major reasons for the small overall effect size Evans et al. observed in their "walk in the park if you will" study. Eventually, the preservation of an already low amount of lean tissue mass is one thing, increasing the latter and thusly building the metabolic advantage of greater lean muscle mass, based on which the male study participants shed roughly 15% more body fat within the 12 month than their female peers is yet another one, of which I can hardly repeat often enough that it will not turn Angels into Divas over night (see image 2). And while you can easily regain 2 pounds of fat you lost, you will have to acknowledge that the lean mass you have either never built or lost over years of mainstream dieting, won't come back easily (cf. Beavers. 2011).

Image 2 (unkown Facebook source): Strength training and a high protein diet don't turn Angel's into Divas over night - what a pity ;-)
Bottom line: Regardless of whether you are a woman or a man, an angel or a diva, Homer Simpson, Peter Griffin, or Stanley Smith (cf. "Stocktaking, Goal Setting, -Tracking & -Resetting to Achieve a Healthy Weight & Shed Excess Body Fat"), greasy steaks, eggs, fish, dairy and a gym membership will not just have a much more pronounced impact on the outcome of your next diet, than all the diet products and books your money can buy, as an elementary part of your new lifestyle they will also lay the foundation of your future health - and what's even better: You will have more than enough extra years to spend all the money you would otherwise have spent on all those gimmicks, false promises, useless supplements and defacing cosmetic surgeries! Now you tell me eating a high(er) protein diet and spending time in the gym instead of the office was uneconomical ;-)

References:
  1. Beavers KM, Lyles MF, Davis CC, Wang X, Beavers DP, Nicklas BJ. Is lost lean mass from intentional weight loss recovered during weight regain in postmenopausal women? Am J Clin Nutr. 2011 Sep;94(3):767-74. Epub 2011 Jul 27.
  2. Evans EM, Mojtahedi MC, Thorpe MP, Valentine RJ, Kris-Etherton PM, Layman DK. Effects of protein intake and gender on body composition changes: a randomized clinical weight loss trial. Nutr Metab (Lond). 2012 Jun 12;9(1):55.
  3. Krebs JD, Elley CR, Parry-Strong A, Lunt H, Drury PL, Bell DA, Robinson E, Moyes SA, Mann JI. The Diabetes Excess Weight Loss (DEWL) Trial: a randomised controlled trial of high-protein versus high-carbohydrate diets over 2 years in type 2 diabetes. Diabetologia. 2012 Apr;55(4):905-14. 
  4. Washburn RA, Kirk EP, Smith BK, Honas JJ, Lecheminant JD, Bailey BW, Donnelly JE. One set resistance training: effect on body composition in overweight young adults. J Sports Med Phys Fitness. 2012 Jun;52(3):273.