Overweight people are more likely to have heart disease, diabetes, heartburn or gastric reflux, and gallstones than those who are within a ‘normal’ weight range. In very obese people breathing may be very difficult, particularly at night when sleeping. Reducing weight to reach a healthy weight range reduces most of these risks. 

Life expectancy is generally reduced in obese people. Maintaining a healthy weight also makes exercise and movement easier. Exercise is also important in maintaining a healthy body and reducing the risks of some diseases.