Nutrition in a changing world: How economic growth drives chronic diseases

Abstract

Many modernizing countries are characterized by a dual nutritional burden-the simultaneous presence of undernutrition and obesity within populations, households, or even individuals. The dual burden is a primary risk factor for the epidemic of chronic degenerative diseases affecting such populations, and may benefit from an evolutionary perspective. Evolving in environments of ecological instability, the genus Homo developed a complex life history profile with multiple "nodes of flexibility" whereby the magnitude and rate of growth are sensitive to diverse ecological stresses. Through such plasticity, preagricultural populations could tolerate ecological instability, through time-lagged physiological sensitivity to fluctuating energy availability. This plasticity now renders contemporary populations vulnerable to new sources of nutritional instability, emerging from the role played by capitalist economics in the global supply and distribution of food. Chronic diseases emerge when rapid economic growth elevates metabolic load (adiposity, high-energy diet, sedentary behavior) over short-time scales in the absence of complementary effects on homeostatic capacity. An evolutionary perspective emphasizes the sensitivity of human metabolism to politico-economic factors driving nutritional trends. Successful prevention of chronic diseases is unlikely to occur without efforts to alter the power structures that characterize the contemporary food- industrial complex, restoring individual agency over diet and activity behavior.