Method: We compute body mass index (BMI: kg/m2) and sex- and age-specific z-scores using international reference standards for BMI, weight, and height among children. We use available waves of periodically collected surveys including the China Health and Nutrition Survey, Indonesian Family Life Survey, India’s National Family and Health Survey, and the US National Health and Nutrition Examination Survey. Outcomes are stratified by sex and age (children, adults (15-45 years), elderly (65+ years)).
Result: The distribution of BMI among the Chinese population has shifted to the right over time, resulting in reductions in underweight prevalence and increases in obesity with larger shifts for the elderly and adult men. BMI distributions of adult women have not changed substantially. In stark contrast, Indonesia’s largest shifts in BMI distribution occur among adult women and children. Obesity has not changed measurably among the elderly where underweight prevalence among elderly, though declining, remains high. While Indian data are sparse, there is no evidence of substantial reductions in underweight status or increases in obesity among young children or adult women or men. In all countries, an apparent paradoxical drop in children’s BMI distributions is due to increases in height-for-age preceding and exceeding increases in weight-for-age, though weight continues to increase after height distributions stabilize. Trends in Asian countries appear similar to trends in the US during the 1970s, and if they continue, obesity with long exposure starting in childhood could become the norm along with obesity-related chronic disease.
Conclusion: Economic development has reduced undernutrition but has done so unequally with some groups becoming obese while others are remaining undernourished (i.e., the elderly, women). The heterogeneous examples of China, Indonesia, and India suggest that economic growth has the potential to alter the dynamics of nutritional inequality, threatening higher and longer-term obesity and related chronic disease exposure in the future elderly even with the persistence of undernourished subpopulations.