Weight gain is as difficult as losing it, if you are naturally thin. Gaining weight is a problem for many people. They complain that they can't put on any weight. Following are some tips to follow to gain weight. You will take some time to gain the weight you need, but be patient.

1. Consume more calories than you burn. Choose healthy foods to add calories.
   Drink healthy beverages to add calories.(Orange juice and yogurt drinks counted? )
   Mangoes are rich in calories and carbohydrates, include them in your diet. (alright Noted mangoes!)
2. Eat healthy food frequently, 5-6 times a day - 3 larger meals and 3 smaller meals alternately. Separate them by at least 3 hours so you can digest each meal fully. Don't go without food for 5-6 hours after having a major meal. (OMG i always do that. Never eat the whole day then one meal settle all! :x )
   For example, if you wish to consume 3000 calories a day, you may eat 3 larger meals of about 650 calories and 3 smaller meals of about 450 calories.
3. Have a balanced diet.
4. Exercise regularly for healthy weight gain. Some thin people think that exercise is not good for them. This is not true, it keeps the metabolism high. Remember that eating alone is not sufficient. You don't want to gain fat but lean mass, so exercise is important. ( hehe that's what i always thought :x)
   Resistance training exercises will help to increase your muscle mass, which in turn will increase your metabolism. Learn to distinguish between weight gaining exercises and weight loss exercises.
   Note that if you do not get enough amino acids during exercise, the existing muscle may break down. Amino acids come from protein rich foodsso you should eat such foods after exercise.

   Weight Gaining Foods

5. Protein is the key for the muscle mass. Without adequate protein, muscle gain is not possible because weight training demand for amino acids (which comes from protein).
   You should daily eat about 2.2g of protein per kilogram (1g per pound) of your weight. For example, if you are 50kg (110pound), then you should eat 50x2.2=111g of protein spread over 5-6 meals in the day. Include high protein foods in your diet. Your protein intake should be from foods rather than from supplements.
   Good sources of protein foods: whey, fish, dairy products (low fat variety), meats, nuts and seeds (almonds, peanuts, pumpkin seeds, sesame seeds, sunflower seeds). (OMG! Dear is so clever la.. he told me all this! hao de i know liao :D I dun lived in cave hor! )

   Milk is one of the best muscle foods.
   The milk contains two high quality proteins, about 80 percent whey and 20 percent casein. Whey is quickly broken down into amino acids and absorbed into the bloodstream. Whey is very good to consume after workout. Casein is digested more slowly and provides the body with a steady supply of protein for a longer period of time. (YA I got eat cheese one. But seldom drink milk.. Will start drinking milk. )
   Milk nutrition | Protein in Milk, Cheese, Yogurt

6. Healthy fats: Avoid fatty foods. Most mothers, especially in India give too much ghee or butter to their children, thinking they will gain weight fast. But ghee is mostly saturated fat which is not a healthy fat for any body. Healthy fats are monounsaturated and polyunsaturated fats and omega-3 essential fatty acids.
   Good fats: cold pressed oils (olive, sunflower, linseed, canola, best cooking oil)
7. Complex carbohydrates are also needed.
8. Some people think that drinking beer helps gain weight. But it is not true, it accumulates in your abdomen, making it fatty. (hehe dear! BEER BELLY! :p)
9. Don't take protein supplements. Consult your doctor for protein supplements.