Around the world, obesity is on the rise. A global uptick in body mass index, or BMI — a measure of whether a person’s weight is healthy for how tall they are — has coincided with rapid urbanization, leading to the assumption that urbanization is the main reason behind the global obesity epidemic.

Now, a large new report reveals the rise of global BMI comes from people living in rural areas rather than people living in urban areas. The finding contrasts theories that urban lifestyles cont