Authors
McCargar LJ. Baracos VE. Clandinin MT.
Institution
Department of Foods & Nutrition, Faculty of Home Economics, University of
Alberta, Edmonton, Canada.
Title
Influence of dietary
carbohydrate-to-fat ratio on whole body nitrogen retention
and body composition in adult rats.
Source
Journal of Nutrition. 119(9):1240-5, 1989 Sep.
Abstract
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.