Why do gains in weight always seem to go on the same place?
One’s body tends to deposit fat according to your individual genetic code. In other words, hereditary characteristics dictate areas in your body that accumulate fat. If you are a typical female, you will accumulate fat around your thighs and hips. Typically, males accumulate fat around the midriff and lose it there last

Can I get fat off from a specific part of the body?
The simple answer is NO. If you exercise a particular part of the body, muscle tissue under the fat will become firm and make the overall appearance of that region look better. However, such specific exercise will not reduce the quantity of fat within the area. Thus, simply by jogging one will not just reduce the fat around the legs and hips, the fat providing energy for this activity may be coming from the stomach, chin, back etc.

Fats, which consist of a wide group of compounds, are usually soluble in organic solvents and insoluble in water. Chemically, fats are usually known as triesters of glycerol and fatty acids (triester = one of three ester chemical groups).
Fat is one of many essential nutrients. Dietary fat is the most “fattening” nutrient we eat. It provides 9 calories, units of energy, per gram.Carbohydrates and proteins each provide 4 calories per gram.
When dietary fat is digested, fatty acids are produced. One fatty acid, the essential linoleic acid, helps us absorb fat-soluble vitamins and minerals. It is also important for healthy skin and blood pressure regulation.