Understanding how cells become fat cells is a crucial part of tackling conditions like obesity and type 2 diabetes – and a new study just gave us some important clues into how we might prevent them from turning into fat cells. The Hippo pathway is fundamental in controlling how big our organs grow, essentially by deciding whether cells should divide, die, or become a specific type, such as fat cells. Rather than reverting fully to stem cells, these fat cells lost many of their defining fat-cell features and behaved more like precursor cells. And once fat cells form, they are difficult to eliminate; when we lose weight, fat cells tend to shrink, rather than disappear completely. Understanding how PPARγ does (or doesn't) work in coaxing cells into being fat cells could one day offer new ways to treat metabolic disease.