Wednesday, April 13, 2011

Calorie Restriction vs. Exercise for Optimal Body Composition? Exercise Preserves Muscle Tissue and Prevents Metabolic Downregulation.

Those of you who listened to my comments on set points and reasonable weight loss on Super Human Radio, will already know that - other than Gary Taubes, for example - I am a huge advocate of exercise, when it comes to weight loss, -maintenance and overall improvements in body composition. Data from a recently published study (Soare. 2011), despite being evaluated from an anti-aging perspective, confirms the adequacy of approaching your body composition goals, by dietary modifications and exercise induced increases in energy expenditure, instead of just "eating less calories".

In their study, Soare et al compared 24 subjects who had been on a calorically restricted diet (CR, 1769±348 kcal/d) for an average of 6 years to 24 age- and sex-matched sedentary individuals (control, WD, 2302±668 kcal/d) and 24 body fat-matched exercise-trained (EX, 2798±760 kcal/d) volunteers, who were eating Western diets.
Figure 1: Total body weight, lean mass & fat mass in sendentary control, calorie restricted (CR) and exercise (EX) group. (Data adapted from Soare. 2011)

Although the researchers found that both, "the CR and EX groups were significantly leaner than the control (WD) group" both the greater amount of lean body mass (cf. figure 1) as well as their finding that...
Mean 24-hour, day-time and night-time core body temperatures were all significantly lower in the CR group than in the WD and EX groups (P≤0.01).
...underline the futility of every effort to achieve improved body composition, i.e, to maximize muscle (lean mass), while shedding as much body fat, as possible via (even moderate) caloric restriction.

Two other things are noteworthy, as well. Firstly, the reduction in body temperature, which is indicative of a downregulation of the metabolic rate, may be favorable for a longer, but that does not equate into more livable life. And secondly, the "Taubes-Hypothesis" that exercise is "useless", because "it makes you hungry" (the subjects in the EX group in fact consumed more calories) and you would compensate by eating more, anyway, would be relevant, only, if in fact "a calorie was a calorie" and "only calories" counted; the superior body composition of the exercise group, on the other hand, speaks for itself and does suggest that even Garry himself may benefit from one or another training session in the gym ;-)

Edit: As I hear in an anonymous comment Taubes is supposed to do resistance training. When he was talking to doctor Oz, he did however propose the hypothesis I refer to above and this really bothered me.