The reduced energy intake of rats fed a high-protein low-carbohydrate diet explains the lower fat deposition, but macronutrient substitution accounts for the improved glycemic control.
The metabolic effect of high-protein low-carbohydrate (HP) diets on body composition and glucose homeostasis remains incompletely understood. This study assesses the respective roles of the increased protein:carbohydrate ratio (P:C) and the resulting moderate decrease in energy intake in the metabolic effects of HP diets. Rats had free access to normal (NP; 14%) or high (HP; 53%) total milk protein isoenergetic diets, or were fed the NP diet but restricted to the energy intake of HP rats (NPr), which was 89.1 +/- 9.3% that of NP rats. After 8 wk, body weight was lower in HP and NPr rats than in NP rats. In HP rats, the lower body weight was associated with a lower adipose tissue mass and a reduced proportion of large adipocytes. HP rats also had an improved oral glucose tolerance and insulin sensitivity, as assessed by the homeostatic model assessment index, compared with NPr and NP rats, and these effects were related solely to the increased P:C. These data suggest that the reduced energy intake of rats fed a high-protein, low-carbohydrate diet explains the lower fat deposition but an increased P:C per se improves glucose homeostasis.
Blouet
Clémence
C
UMR 914 INRA/INA P-G Physiologie de la Nutrition et du Comportement Alimentaire, Institut National Agronomique Paris-Grignon, Paris, France.
Mariotti
François
F
Azzout-Marniche
Dalila
D
Bos
Cécile
C
Mathé
Véronique
V
Tomé
Daniel
D
Huneau
Jean-François
JF
D000818:Animals; D001786:Blood Glucose / Q000187:drug effects; D001823:Body Composition / Q000187:drug effects*; D004040:Dietary Carbohydrates / Q000008:administration & dosage / Q000494:pharmacology*; D004044:Dietary Proteins / Q000008:administration & dosage / Q000494:pharmacology*; D002149:Energy Intake; D005947:Glucose / Q000378:metabolism*; D006706:Homeostasis / Q000187:drug effects*; D008099:Liver / Q000187:drug effects / Q000378:metabolism; D008297:Male; D051381:Rats; D017208:Rats, Wistar
D001786:Blood Glucose; D004040:Dietary Carbohydrates; D004044:Dietary Proteins; D005947:Glucose