Researchers at Washington University School of Medicine in St. Louis have identified a way to prevent fat cells from growing larger, a process that leads to weight gain and obesity. By activating a pathway in fat cells in mice, the researchers found they could feed the animals a high-fat diet without making them obese.

Microbes that live in the gut don’t just digest food. They also have far-reaching effects on the immune system. Now, a new study shows that a particular gut microbe can prevent severe flu infections in mice, likely by breaking down naturally occurring compounds — called flavonoids — commonly found in foods such as black tea,…