Total daily energy expenditure in black and white, lean and obese South African women.
OBJECTIVE
In South Africa (SA), the prevalence of obesity in women is 56%, with black women being most at risk (62%). Studies in the United States have demonstrated ethnic differences in resting (REE) and total daily energy expenditure (TDEE) between African American (AA) and their white counterparts. We investigated whether differences in EE exist in black and white SA women, explaining, in part, the ethnic obesity prevalence differences.


METHODS
We measured REE, TDEE and physical activity EE (PAEE) in lean (BMI <25 kg m(-2)) and obese (BMI >30 kg m(-2)) SA women (N=44, 30+/-6 year). REE, TDEE, PAEE and total awake EE were measured during a 21 h stay in a respiration chamber.


RESULTS
Black and white subjects within obese and lean groups were not significantly different for age, mass, BMI and % body fat. However, fat-free mass (kg FFM) was consistently lower in the black women (P<0.01) in both weight groups. After adjusting EE measurements for differences in FFM, REE was not significantly different for either body weight or ethnicity, although 24 h TDEE (kJ) was significantly greater in the obese women (P<0.01) and white women (P<0.05). Total awake non-PAEE was not significantly different for either groups, while total awake time was only significantly lower for the lean groups (P<0.01). Total PAEE (kJ min(-1)) was significantly lower in the lean (P<0.001) and black groups (P<0.01).


CONCLUSIONS
In this sample of matched, lean and obese, black and white SA women, differences in TDEE were largely explained by ethnic differences in PAEE, and were not as a result of ethnic differences in REE.
Dugas
L R
LR
MRC/UCT Research Unit for Exercise Science and Sports Medicine, Department of Human Biology, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa. Ldugas@lumc.edu
Cohen
R
R
Carstens
M T
MT
Schoffelen
P F M
PF
Luke
A
A
Durazo-Arvizu
R A
RA
Goedecke
J H
JH
Levitt
N S
NS
Lambert
E V
EV
D000273:Adipose Tissue; D000328:Adult; D000367:Age Factors; D044383:Black People; D015992:Body Mass Index; D001835:Body Weight; D004032:Diet; D004734:Energy Metabolism; D015444:Exercise / Q000502:physiology*; D005260:Female; D006801:Humans; D009765:Obesity / Q000208:ethnology / Q000378:metabolism*; D012146:Rest; D013019:South Africa; D049629:Waist-Hip Ratio; D044465:White People; D055815:Young Adult; D001741:Black or African American