This research is motivated by two stylized facts: (i) the weak relationship between income and nutritional status in developing countries, and (ii) the increased prevalence of noncommunicable diseases; in particular, cardiometabolic diseases among normal weight individuals, with economic development. Our unified explanation for these stylized facts is based on a nutrition trap: a growing biomedical literature posits that there exists an epigenetically determined set point for each individual’s body weight, with metabolic and hormonal adjustments defending the set point in response to variation in energy intake (food consumption). Consumption within a range of the set point thus fails to change nutritional status, but once consumption crosses a threshold, the body can no longer defend the set point and the resulting metabolic imbalance increases the risk of cardiometabolic diseases (diabetes, hypertension, and cardiac disease). The set point in a given population is partly determined by conditions in the pre-industrial economy, allowing us to explain variation in the income-nutritional status relationship and the BMI-diabetes relationship across broad regions of the world. To establish that a set point does indeed exist, we develop a model that generates predictions for the cross-sectional relationship between current income and both nutritional status and cardiometabolic diseases when a nutrition trap is present. These predictions are tested with microdata from India, Indonesia, and Ghana. Estimation of the model’s structural parameters allows us to quantify the impact of the nutrition trap, which turns out to be substantial, explaining approximately 40% of under-nutrition in India.
Written with Anu Alexander (Christian Medical College, Vellore), Nancy Luke (Pennsylvania State University), and Swapnil Singh (Central Bank of Lithuania).