Hi Sana, I understand your concern. It is always advisable to gain weight by natural means through diet and gradually rather than drugs as they would have certain adverse effects on the body. You can consume calorigenic foods in the form of more quantity of carbohydrates, moderate quantity of fats and more quantity of proteins along with adequate quantity of vitamins and minerals regularly. Along with the regular diet include calorigenic fruits like plantain or apple or jack fruit regularly and a glass of milk at bedtime. Avoid eating junk foods. You need to keep a check on excessive weight gain by consuming good quantity of fluids and regular moderate exercise. Gradually, it should help you to gain sufficient quantity of weight in a reasonably healthy way. Hope the information provided would be helpful. All the best.