Everything we know about dieting and weight loss is wrong. In the UK, almost two-thirds of adults are overweight. We think we know the answer: cut calories; eat less. We conclude that being fat is a failure of willpower, perhaps supplemented by a quirk of genetics. Yet research shows that losing weight by willpower alone is almost guaranteed to fail in the long run. In fact, there is no evidence that dieting improves long-term health, and some that suggests yo-yo dieting is more dangerous than being overweight. Combining deep research and brutal candour about her own experience as a yo-yo dieter, neuroscientist Sandra Aamodt explains the science of the obesity epidemic, including new findings about gut bacteria, why bariatric surgery works (it has more to do with your brain than your stomach), and what a real alternative to dieting and weight cycling might look like.