Expert doctors say something must be done straight away about obesity.
Leading doctors from three medical colleges say the government, the food industry and other doctors should work together to solve the growing problem.
Obesity, or being very overweight, can cause health problems like heart disease and diabetes.
They warn that unless something is done very quickly, at least a third of adults, a fifth of boys and a third of girls will be obese by 2020.
Hear story
Body Image webchat
Healthy eating quiz
