Energy expenditure and obesity across the economic spectrum

Abstract

Global economic development has been associated with an increased prevalence of obesity and related health problems. Increased caloric intake and reduced energy expenditure are both cited as development-related contributors to the obesity crisis, but their relative importance remains unresolved. Here, we examine energy expenditure and two measures of obesity (body fat percentage and body mass index, BMI) for 4,213 adults from 34 populations across six continents and a wide range of lifestyles and economies, including hunter-gatherer, pastoralist, farming, and industrialized populations. Economic development was positively associated with greater body mass, BMI, and body fat, but also with greater total, basal, and activity energy expenditure. Body size-adjusted total and basal energy expenditures both decreased approximately 6 to 11% with increasing economic development, but were highly variable among populations and did not correspond closely with lifestyle. Body size-adjusted total energy expenditure was negatively, but weakly, associated with measures of obesity, accounting for roughly one-tenth of the elevated body fat percentage and BMI associated with economic development. In contrast, estimated energy intake was greater in economically developed populations, and in populations with available data (n = 25), the percentage of ultraprocessed food in the diet was associated with body fat percentage, suggesting that dietary intake plays a far greater role than reduced energy expenditure in obesity related to economic development.

Keywords: doubly labeled water; energy expenditure; obesity; physical activity.

Fig. 1.

Body size and composition across economies. Cohorts are ordered from lowest to highest HDI score. Bars indicate mean and quartiles. (A–D) Body mass, height, BMI, and body fat percentage increase with economic development in both women and men. Substantial portions of the BMI distribution fall above the criterion for obesity (BMI ≥ 30 kg/m²) in Low, Mid, and High HDI populations. (E–H) There is considerable variability within and between populations in age- and sex-adjusted body mass, height, BMI, and body fat percentage. See SI Appendix, Table S8 for population measures and abbreviations.

Fig. 2.

Energy expenditure across economies. (A–D) TEE, BEE, and AEE increase with economic development. Bars indicate mean and quartiles. (E–H) Adjusted expenditures, calculated from residuals from multiple regression with FFM, FM, age, and sex varied considerably within and between populations. Size-adjusted TEE and BEE (residuals from regression with FFM, FM, sex, and age) decreased weakly with economic development. PAL and size-adjusted AEE were unrelated to economic development. Populations with measured basal expenditures are indicated with _M, estimated with _E.

Fig. 3.

The relationship between energy expenditure, adiposity, and BMI. The relationship between TEE and body fat percentage (A and B) and BMI (C and D) differed between women and men. The relationship between FFM-adjusted TEE and body fat percentage (E–H) and BMI (I–L) was weak, highly variable, and distributed about 0 among populations (SI Appendix, Tables S4 and S5).

Fig. 4.

UPF and adiposity. The percentage of daily calorie intake from UPF was positively associated with body fat percentage in bivariate analyses and in multiple regression including FFM-adjusted total expenditure, age, sex, and HDI rank (SI Appendix, Table S5).