What makes people overweight?

People gain weight when the number of calories they eat is more than the number of calories their bodies use. Many factors can play a part in weight gain.
Habits.

Eating too many calories can become a habit. So can choosing activities like watching TV instead of being physically active. Over time, these habits can lead to weight gain.
Genes.

Overweight and obesity tend to run in families. Although families often share diet and physical activity habits that can play a role in obesity, their shared genes increase the chance that family members will be overweight.
Illness.

Some diseases can lead to weight gain or obesity. These include hypothyroidism, Cushing’s syndrome, and depression. Talk to your health care provider if you think you have a health problem that could be causing you to gain weight.
Medicine.

Some medicines can lead to weight gain. Ask your health care provider or pharmacist about the side effects of any medication you are taking.
The world around you.

You can find food and messages about food at home, at work, at shopping centers, on TV, and at family and social events. People may eat too much just because food is always there. On top of that, our modern world—remote controlled televisions, drive-in banks, and escalators—makes it easy to be physically inactive.
Emotions.

Many people eat when they are bored, sad, angry, or stressed, even when they are not hungry.
Although you may not be able to control all the factors that lead to overweight, you can change your eating and physical activity habits