Agreed with Dr. Khan. Also, Keep a watch on what you eat, and make sure its nutritious.
TO Gain weight add more carbohydrates in your diet. Carbohydrates come from a wide array of foods - bread, beans, milk, popcorn, potatoes, cookies, spaghetti, corn, and cherry pie. baked potatoes, sweet potatoes, dry futis, banana, grapes, pine apple and dairy products Milk. They also come in a variety of forms. The most common and abundant are sugars, fibers, and starches.