Low ratio of fat to carbohydrate oxidation as predictor of weight gain: study of 24-h RQ.
Reduced oxidation of fat leading to a positive fat balance could be a factor in the development of obesity. Twenty-four-hour respiratory quotient (RQ) was measured in 152 nondiabetic Pima Indians fed a weight-maintenance diet [87 males and 65 females; 27 +/- 6 yr (mean +/- SD); 93.9 +/- 22.9 kg; 32 +/- 9% fat]. Twenty-four-hour RQ varied from 0.799 to 0.903. Prior change in body weight, 24-h energy balance, sex, and percent body fat explained 18% of the variance in 24-h RQ (P less than 0.001). In a subgroup of 66 siblings from 28 families, family membership explained 28% of the remaining variance in 24-h RQ (P less than 0.05). In 111 subjects for whom follow-up data (25 +/- 11 mo) were available, 24-h RQ was correlated with subsequent changes in body weight and fat mass (r = 0.27, P less than 0.01 and r = 0.19, P less than 0.05, respectively). Subjects with higher 24-h RQ (90th percentile) independent of 24-h energy expenditure were at 2.5 times higher risk of gaining greater than or equal to 5 kg body weight than those with lower 24-h RQ (10th percentile). We conclude that in Pima Indians fed a standard diet 1) family membership is the principal determinant of the ratio of fat to carbohydrate oxidation, and 2) a low ratio of fat to carbohydrate oxidation is associated with subsequent weight gain independent of low energy expenditure and may contribute to the familial aggregation of obesity.
Zurlo
F
F
Clinical Diabetes and Nutrition Section, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Phoenix, Arizona 85016.
Lillioja
S
S
Esposito-Del Puente
A
A
Nyomba
B L
BL
Raz
I
I
Saad
M F
MF
Swinburn
B A
BA
Knowler
W C
WC
Bogardus
C
C
Ravussin
E
E
D000328:Adult; D001130:Arizona; D001786:Blood Glucose / Q000378:metabolism; D001823:Body Composition; D001835:Body Weight; D004040:Dietary Carbohydrates / Q000378:metabolism*; D004041:Dietary Fats / Q000378:metabolism*; D004734:Energy Metabolism; D005230:Fatty Acids, Nonesterified / Q000097:blood; D005260:Female; D006801:Humans; D007198:Indians, North American; D007328:Insulin / Q000097:blood; D008137:Longitudinal Studies; D008297:Male; D012119:Respiration; D015430:Weight Gain
D001786:Blood Glucose; D004040:Dietary Carbohydrates; D004041:Dietary Fats; D005230:Fatty Acids, Nonesterified; D007328:Insulin