People gain weight and get fat when they consistently eat more calories than their bodies require meeting daily demands. This excess calories get stored as fat. We gain weight when we eat more than we can burn off. But this conventional diet wisdom does not always hold true. Weight gain can also be caused by health conditions such as hypothyroidism, food sensitivity, Cushing's syndrome, organ disease, prescription drug use, anxiety, blood sugar imbalance, and essential fatty acid deficiency. We also gain weight as we age. As we age, a decrease in our physical abilities leads to a decrease in our metabolic rate, which in turn contributes to weight gain. The physiological changes that accompany increasing age affect the body's composition and heart and lung function, thus reducing our ability to work and exercise and lose weight. Genetics, muscle mass, gender, calorie consumption versus expenditure, and lifestyle are all factors in weight gain. Regular exercise helps to preserve muscle mass, particularly muscle loading exercises such as weight training, walking, and physically challenging occupations.

Weight-gain is not a head cold or a boil that magically appears overnight. Like muscle, it's something that increases gradually with time and with your complete awareness and collaboration. Building muscle is hard and takes lots of exercise, whereas getting fat is pretty easy and requires no exercise at all.

Causes of gaining weight

• Drink anything but water

• Don't walk

• Genetics

• Grow older

• Eat junk food

• Eat more calories

• Eat out regularly

• Excessive alcohol

• Never read food labels

• No exercise

• Pregnancy

• Stress

Everyone needs some amount of fat to survive, but when the fat cells become too excessive, the body starts to place the extra fat in places like liver cells, muscle cells and heart cells, which doctors believe may be causing health problems.