One reason for your challenges in gaining weight might be a high metabolism, stress, a bad diet, or a health issue. It is ideal to visit a doctor to determine the root of the problem. They will suggest a dietitian, who would be able to help you find ways to consume healthy foods that will help you in increasing your weight on a gradual basis. Medicines are generally not recommended for weight maintenance. Rather than only thinking about weight goals, concentrate on the intake of fruit, vegetables, whole grains, and protein which contribute to weight strengthening and may enhance it. Lean gaining should be looked at from a healthy perspective, and the best way forward is the help of health professionals.