Energy expenditure and physical activity comparable between developing and industrialized countries: results of a meta‐analysis

The etiology of overweight is unclear at the population level, ultimately, however, it must be due to imbalance of energy intake and expenditure. Despite a paucity of comparative data, it is accepted that populations in developing countries expend more energy than those in industrialized countries. We tested this assumption by conducting a meta‐analysis of published doubly labeled water studies. The methods included a search of literature and extraction of relevant data: cohort size, sex, age, weight, body mass index (BMI), total energy expenditure (TEE) and physical activity level (PAL). Cohorts were assigned either developing or industrialized country status by ranking of the U.N. Human Development Index (HDI). Analyses included estimation of TEE and PAL using both fixed and random effects models. Meta‐regression was performed to assess impact of HDI status on TEE or PAL controlling for sex, age, and body size. 89 studies and 166 discrete cohorts were identified. Mean BMI was lower in the low HDI (n=21) than high HDI (n=145) group, 22.8 vs 26.3 (p<0.01). Overall mean TEE was 2555 kcal/d and PAL was 1.73. TEE was associated with weight and sex and inversely associated with age (all p<0.001). PAL was associated with sex (p<0.05). Neither mean TEE nor PAL differed between low or high HDI countries. These data support the idea that energy intake may play a greater role than expenditure in population differences in obesity.