Total daily energy expenditure in black and white, lean and obese South African women

Abstract

Background/Objectives: 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. Subjects/Methods: We measured REE, TDEE and physical activity EE (PAEE) in lean (BMI o25 kg m À2 ) and obese (BMI 430 kg m À2 ) SA women (N ¼ 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 (Po0.01) 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 (Po0.01) and white women (Po0.05). Total awake non-PAEE was not significantly different for either groups, while total awake time was only significantly lower for the lean groups (Po0.01). Total PAEE (kJ min À1 ) was significantly lower in the lean (Po0.001) and black groups (Po0.01). 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.

Resting Energy Expenditure of Black Overweight Women in South Africa Is Lower than of White Women

“…This study showed that, in contrast with a previous South African study [15] but in accordance with international studies [5,6,16], black overweight women in South Africa have a lower REE than white women. The mean differences of 585 and 861 kJ between races/ethnicities (after adjusting for BMI and FFM, and FFMI, respectively) are statistically significant and similar to previously reported differences of 576 kJ/day [16], 340-1,151 kJ/day [6] and 210-672 kJ/day [5].…”

“…This contrasts American studies where black women had a similar or greater FFM [5,6,26]. The difference could be explained by the fact that black women in this study (table 2) and in the other South African study were shorter than white women [15]. American studies showed no height difference between races/ethnicities [26].…”

“…Similar to the only other known South African study, this research resulted in a statistically significant lower FFM in black than white women, although percentage body fat and FM were similar [15]. This contrasts American studies where black women had a similar or greater FFM [5,6,26].…”

“…Unpublished observations at our institution confirmed a significant overestimation of REE in normal-weight South African black women. The only study investigating a race/ethnicity difference in overweight women in South Africa had a very limited sample size and did not find a significant difference between black and white women [15]. We are not aware of South African studies investigating the accuracy of equations estimating REE, particularly across race/ethnicity.…”

Ethnic differences in the association between lipid metabolism genes and lipid levels in black and white South African women

“…However, it is more likely that ethnic differences in the relationships between the LPL X and CETP B2 allele and serum lipid levels are due to differences in lifestyle factors between black and white SA women, specifically the intake of dietary fat [6,7,41]. We have previously shown that black women consume more energy, particularly as dietary fat, than white women [26,42,43].…”