Cambridge scientists have solved the mystery of why both stimulating and blocking a particular ‘switch’ in the brain can help people lose weight – findings which could help boost the effectiveness of obesity drugs. Weight loss can help mitigate these complications, but losing weight through diet and exercise alone can prove challenging. In the past few years, a new generation of weight loss drugs has emerged that target particular receptors in the brain, reducing appetite and leading to weight loss, as well as helping control blood sugar levels. Other weight loss drugs act on both this receptor and a second one, the glucose-dependent insulinotropic polypeptide receptor (GIPR). Obesity drugs are not acting simply on the gut or pancreas.