Abstract
This paper estimates the causal effect of online food delivery platforms on body weight in China. Exploiting the staggered rollout of Eleme across Chinese cities between 2010 and 2020, we find that platform entry shifts the BMI distribution rightward among urban young adults: it increases body mass index, lowers underweight prevalence, and raises the likelihood of being overweight. Effects are negligible among urban older adults, consistent with lower platform adoption in this group. Mechanism analysis points to shifts in dietary preferences toward energy-dense foods, reduced meal preparation time, and increased restaurant entry. Our findings highlight the health trade-offs associated with digital food platforms in rapidly urbanizing developing countries, where improved caloric access may coexist with greater exposure to lower-quality, energy-dense foods.