Hello, Eat three meals per day, as well as two snacks. Focus on hefty foods. You don't have to exclusively eat high-fat foods to gain weight. Avoid ready-made mades , fast foods . Eat more protein like Boiled soybeans,Soy or whey protein powder,Peanuts or peanut butter,Steak or hamburger,Chicken.Do aerobic exercise daily ,it helps to increase appetite .