Friday, January 14, 2011

The Great Feast: Overeating With a Macronutrient Emphasis on Carbs Suppresses GH Levels Via Hyperinsulinemia

An interesting study done by scientists from the Department of Internal Medicine (A.L.B.) at the University of Michigan (Cornfold. 2011) reveals a direct influence of overeating (+75% over maintenance) and the associated rise in insulin on growth hormone levels.

Cornfold et al. found that GH levels of seven (formerly ;-) healthy, nonobese men (body mass index, 24 ± 1 kg/m2; age, 25 ± 1 yr) "declined nearly 80% by d 3 of overeating".
Figure 1: Mean plasma GH concentration every 20 min for 24 h before overeating
(baseline), ond3of overeating, and at the end of the 2-wk overeating period. Inset,
The average plasma GH concentration at baseline, d 3, and 2 wk of overeating.
In view of some people's "eat all that cannot run away fast enough" mass gain diets, it is noteworthy that the decline in GH concentration is not an initial reaction. As it is shown in figure 1, GH response stayed way below baseline for the whole 2 weeks the subjects ate their standardized meals containing 70 kcal/kg fat-free mass/d (~4000 kcal/d; 50% carbohydrate, 35% fat, and 15% protein).

So, what can we conclude from that? A dirty / extreme bulk with a high carb intake will ruin your GH levels, spike your insulin levels and set the stage for fantastic, or should I say "fatastic", mass or rather fat gains.