Can Temperature Shock Lead to Higher Spending on Unhealthy Foods among U.S. Households

Rising temperatures may influence everyday food choices in ways that have important implications for nutrition and public health. This paper studies how short-run exposure to extreme temperatures affects the composition of household grocery purchases in the United States. Using a nationally representative household panel dataset of grocery transactions merged with local weather information, we exploit within-household variation and estimate two-way fixed effects models to identify causal effects. We find that hotter weeks consistently shift food purchases toward less healthy items and reduce overall diet quality, with little change in total grocery spending. In contrast, unusually cold weeks lead to slight increases in total spending but do not significantly alter the nutritional composition of purchases. These results suggest that heat exposure primarily induces households to reallocate spending toward less healthy foods rather than to change how much they spend, whereas cold exposure mainly affects the volume of groceries purchased. The heat-induced effects on healthiness of food purchases are modest in the short run but are highly robust and more pronounced for households with less healthy baseline purchasing patterns. These findings highlight an underexplored channel through which rising temperatures may degrade diet quality, underscoring the potential public health and welfare costs of climate change.