Diabetes Care, Vol 19, Issue 10 1142-1152, Copyright © 1996 by American Diabetes Association
High-fat and high-carbohydrate diets and energy balance
M Shah and A Garg
Center for Human Nutrition, University of Texas Southwestern Medical Center at Dallas, USA.
The current American Diabetes Association guidelines for nutrition
recommend a moderate increase in monounsaturated fats and a reduced intake
of carbohydrate in patients with diabetes in whom high-carbohydrate diets
deteriorate glycemic control and lipoprotein levels. High-fat diets,
however, are believed to promote obesity, and some investigators may have
reservations recommending such diets. This review thus investigates the
role of diet composition in promoting obesity or achieving weight loss and
its implications in patients with diabetes. Epidemiological studies show
some evidence that fat intake is more importantly related to body weight
than carbohydrate intake, but conclusions are weak because confounding
variables, such as physical activity, smoking, and energy intake, were
generally not controlled for. Metabolic studies under isoenergic conditions
report no change in energy balance when fat intake is increased, but report
a negative fat balance with substantial increase carbohydrate intake.
During overfeeding, excess fat intake is stored as fat, whereas excess
carbohydrate is mostly oxidized in the short term but can lead to
substantial gain in fat stores because of reduced fat oxidation and
considerable de novo lipogenesis in the long term. Spontaneous energy
intake, however, is higher on an unrestricted high-fat diet compared with a
high-carbohydrate diet, but the long-term effects are not known.
Weight-loss intervention studies show that a hypocaloric high-carbohydrate
diet is not associated with more weight loss than a high-fat hypocaloric
diet. In conclusion, a high-monounsaturated fat diet to control glycemic
control and lipoprotein levels in patients with diabetes should not affect
weight loss or maintenance, provided that energy intake is carefully
controlled.