Innate immune responses to high-fat diets lead to obesity

Why is eating a high fat diet a recipe for obesity? According to a new study, the answer involves the activity of a specific type of immune cell that lives in the small intestine. Experiments showed that without group-2 innate lymphoid cells (ILC2s) in the small intestines, mice can eat high-fat diets without gaining extra weight or suffering from other physiological symptoms of obesity.