Effect on 24-h energy expenditure of a moderate-fat diet high in monounsaturated fatty acids compared with that of a low-fat, carbohydrate-rich diet: a 6-mo controlled dietary intervention trial.
BACKGROUND
Dietary fat has a lower thermogenic effect than does carbohydrate. A moderate-fat diet, high in monounsaturated fatty acids (MUFA diet), may decrease energy expenditure (EE) and thereby induce weight gain.


OBJECTIVE
We aimed to compare changes in 24-h EE and substrate oxidation after a 6-mo controlled dietary intervention with either a MUFA or a low-fat (LF) diet.


METHODS
Twenty-seven overweight [body mass index (in kg/m(2)): 28.1 +/- 0.4] nondiabetic subjects aged 18-36 y followed an 8-wk low-calorie diet and a 2-wk weight-stabilizing diet and then were randomly assigned to a MUFA (n = 12) or LF (n = 15) diet for 6 mo. Substrate oxidation and 24-h EE were measured by whole-body indirect calorimetry. The first measurement (0 mo) was taken during the weight-stabilizing diet, and the second measurement was taken after the 6-mo intervention.


RESULTS
A tendency was seen toward a lower 24-h EE with the MUFA than with the LF diet (P = 0.0675), but this trend did not remain after adjustment for the initial loses of fat mass and fat-free mass (P = 0.2963). Meal-induced thermogenesis was significantly (P < 0.05) lower with the MUFA than with the LF diet, but no time x treatment interaction was found. A significant (P = 0.0456) treatment x time interaction was found for spontaneous physical activity.


CONCLUSIONS
Despite a slightly lower meal-induced thermogenesis, the MUFA diet had an effect on 24-h EE that was not significantly different from that of the LF diet after a 6-mo controlled dietary intervention.
Rasmussen
Lone G
LG
Department of Human Nutrition, Faculty of Life Sciences, University of Copenhagen, Frederiksberg, Denmark. logr@life.ku.dk
Larsen
Thomas M
TM
Mortensen
Pia K
PK
Due
Anette
A
Astrup
Arne
A
D000273:Adipose Tissue / Q000378:metabolism; D000293:Adolescent; D000328:Adult; D001481:Basal Metabolism / Q000502:physiology; D001823:Body Composition / Q000502:physiology; D002153:Calorimetry, Indirect; D004038:Diet, Reducing; D004040:Dietary Carbohydrates / Q000008:administration & dosage / Q000378:metabolism*; D004041:Dietary Fats / Q000008:administration & dosage / Q000378:metabolism*; D004734:Energy Metabolism / Q000187:drug effects / Q000502:physiology*; D005229:Fatty Acids, Monounsaturated / Q000008:administration & dosage / Q000378:metabolism*; D005260:Female; D006801:Humans; D008297:Male; D009765:Obesity / Q000453:epidemiology / Q000209:etiology / Q000378:metabolism; D010084:Oxidation-Reduction; D012307:Risk Factors; D022722:Thermogenesis / Q000187:drug effects* / Q000502:physiology
D004040:Dietary Carbohydrates; D004041:Dietary Fats; D005229:Fatty Acids, Monounsaturated