Hi, to gain weight, you have to increase your daily food intake. Increase carbohydrates and protein in your daily diet. Have foods like cheese sandwiches, paneer parathas, aloo parathas, milkshakes, dry fruits like kaju, kismis. Add rice and one extra chapati to your lunch and dinner. Try to have 6 -7 meals in a day, after every 2 - 3 hours instead of only 3 main meals.