What's behind belly fat

How much a person weighs depends in large part on four things:

• Calories taken in each day.
• Calories burned off each day.
• Age.
• Genetics.

Eating and drinking more calories than you burn each day leads to gaining extra weight, including belly fat.

Getting older also plays a role. You lose muscle as you age. And muscle loss is worse if you are not physically active. Loss of muscle mass slows down how quickly the body burns calories. That can make maintaining a healthy weight harder.

Many women notice an increase in belly fat as they get older even if they don't gain weight. This is likely due to a lower level of estrogen because estrogen seems to have an effect on where fat is located in the body.

Your genes can contribute to your chances of being overweight or having obesity too. They also play a role in where the body stores fat.

Drinking alcohol and smoking cigarettes also increase belly fat.