While other diet fads come and go, the ultra low carbohydrate Keto diet seems to endure. But as scientists begin to understand how the diet works, more is also being discovered about its risks. To find out more, Madeleine Finlay speaks to Javier Gonzalez, professor in the department of health at the University of Bath, with a special interest in personal nutrition. He explains how the diet works, what it could be doing to our bodies and what could really be behind the weight loss people experience while on it. Help support our independent journalism at theguardian.com/sciencepod