Weight is balanced by the amount of energy or calories you get from food and drinks (this is called energy IN) equaling the energy your body uses for things like breathing, digesting, and being physically active (this is called energy OUT).

Energy balance means that your energy IN equals your energy OUT. To maintain a healthy weight, your energy IN and OUT don’t have to balance exactly every day. It’s the balance over time that helps you maintain a healthy weight.

Here are some reasons for the excess weight.

• Metabolism: Slows down the metabolism. As we burn calories , our metabolism (metabolism) slows down, so we became more difficult to lose weight.
• Physical Inactivity: Lack of physical inactivity.  We just sit in front of our computers all day and going to transport back and forth.
• Home Work: Working at home is becoming easier. Just look how many of the new washing machines,  computers, remote controls and microwave ovens. Now at home does not require such large amount of energy as before.
• Genetic factors: Some people are predisposed to have more fat cells in your body. You’ve probably noticed how some eat everything, and look healthy (although this is very often not the case), while others are rapidly gaining weight.

• Lack of Sleep: Studies find that the less people sleep, the more likely they are to be overweight or obese. People who report sleeping 5 hours a night, for example, are much more likely to become obese compared to people who sleep 7–8 hours a night.

• Smoking:

  Some people gain weight when they stop smoking. One reason is that food often tastes and smells better. Another reason is because nicotine raises the rate at which your body burns calories, so you burn fewer calories when you stop smoking. However, smoking is a serious health risk, and quitting is more important than possible weight gain.

• Medicines

  Certain medicines such as corticosteroids (for example, prednisone), antidepressants (for example, Elavil^®), and medicines for seizures (for example, Neurontin^®) may cause you to gain weight. These medicines can slow the rate at which your body burns calories, increase your appetite, or cause your body to hold on to extra water—all of which can lead to weight gain.