Hi, hope you are well. For better guidance I need your height and weight as well. To gain weight eat small, energy rich meals every couple of hours. Eg. Fruit or dried fruit milkshakes, banana with honey, add little ghee/oil to vegetables or dals. Have good quality proteins like sprouts, or chaats made from boiled pulses. Add cheese to your sandwich or salads. If you eat predominantly rice then add 1tsp oil/ghee to it. Have 3 fruits per day. Do not too much of fried foods or junk. Hope this guides you.