Determinants of basal fat oxidation in healthy Caucasians.
In a retrospective study, we examined several determinants of basal fat oxidation in 720 healthy Caucasian volunteers. Adult men (n = 427) and women (n = 293) were characterized for resting energy expenditure and substrate oxidation by indirect calorimetry (after a 12-h overnight fast), peak O2 consumption by a treadmill test to exhaustion, body composition by hydrodensitometry, food intake from a 3-day food diary, and hormonal status by fasting hormone concentrations. Fat oxidation was negatively correlated with fat mass in men (r = -0.11; P < 0.05), but no statistical relationship was found in women. In a stepwise multiple regression analysis, fat oxidation was best predicted by peak O2 consumption and fat-free mass in men (model R2 = 0.142) and by free thyroxine, fat-free mass, and fasting insulin in women (model R2 = 0.153). Relative rates of fat oxidation (fat oxidation adjusted for differences in resting energy expenditure) were not correlated with fat mass in either gender. Women showed a lower rate of basal fat oxidation (both absolute and adjusted) than did men. Our results show that fat oxidation is not greater in individuals with a greater fat mass. Furthermore, our results support a sexual dimorphism in basal rates of fat oxidation.
Nagy
T R
TR
Department of Medicine, University of Vermont, Burlington 05405, USA.
Goran
M I
MI
Weinsier
R L
RL
Toth
M J
MJ
Schutz
Y
Y
Poehlman
E T
ET
D000328:Adult; D000368:Aged; D005223:Fats / Q000378:metabolism*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000378:metabolism*; D012737:Sex Factors; D044465:White People
D005223:Fats