We study the causal link between trade openness via free trade agreements (FTAs) and obesity rates. When applying a difference-in-differences approach by exploiting the year a country entered a free trade agreement with the United States during the period 1990–2016. We find a positive and causal impact of FTAs on obesity rates, which are statistically and economically significant. We show that our findings are robust to placebo tests, the use of synthetic control methods, and a maximized sample. Furthermore, we show that when using an event studies approach the equal trends assumption holds.