Influence of dietary carbohydrate-to-fat ratio on whole body nitrogen retention and body composition in adult rats.
Experiments have shown that the amount and source of dietary energy may alter protein metabolism. A high fat diet has resulted in greater nitrogen retention than a high carbohydrate (CHO) diet. To examine this question further, adult rats were fed diets providing ratios of CHO:FAT as a percentage of energy of 0.5, 1.0, 1.5, 2.0, 2.5 or 3.0 for 6 wk. Mean energy and protein intakes were 93.0 +/- 0.8 kcal/d and 5.3 +/- 0.1 g/d, respectively. Final body weight was lower in rats fed the high fat diet (CHO:FAT, 0.5) than in rats fed the high carbohydrate diet (CHO:FAT, 3.0) (P less than 0.05), and a linear response was observed over the entire range of treatments (r = 0.92). Rats fed the high fat diet had the highest nitrogen balance; values were significantly (P less than 0.05) different from those of rats fed high carbohydrate diets (CHO:FAT, 2.0 or 2.5) when expressed as mg nitrogen/kcal energy gain. Rats fed the high fat diet had the highest protein gain and the lowest fat gain as a function of energy gain. It is concluded that alterations in nonprotein energy source result in metabolic changes, which may be related to adaptations in energy expenditure and/or protein deposition.
McCargar
L J
LJ
Department of Foods & Nutrition, Faculty of Home Economics, University of Alberta, Edmonton, Canada.
Baracos
V E
VE
Clandinin
M T
MT
D000818:Animals; D001823:Body Composition / Q000187:drug effects*; D001835:Body Weight / Q000187:drug effects; D004040:Dietary Carbohydrates / Q000032:analysis / Q000494:pharmacology*; D004041:Dietary Fats / Q000032:analysis / Q000494:pharmacology*; D004734:Energy Metabolism / Q000187:drug effects; D008297:Male; D009584:Nitrogen / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains
D004040:Dietary Carbohydrates; D004041:Dietary Fats; D009584:Nitrogen