Obesity is a major public health problem which affects life expectancy and costs billions. It’s also a complex and confusing topic and there is a bewildering array of – often conflicting – information out there about its causes and what we need to do to maintain a healthy body weight. So how can we distinguish between robust scientific evidence and ‘fake news’. In this session, Professor Jason Gill aims to make you an instant expert on diet and obesity by providing evidence-based answers to some of the questions you always wanted to ask on the topic, including: why can some people get fat and stay healthy, but for others even a very small increase in weight can lead to poor health? Which aspects of diet most affect how much we eat and our body weight? Should we be concerned about ultra-processed foods?