To gain weight it is not about eating too much, but eat high energy and protein dense food frequently in small portions. 1 start eating high energy high protein food. Like almond, ground nut, dry coconut, cashew nut, milk and milk products etc 2 do not take stress, if you are suffering from any kind of stress do yoga and meditation 3 quite smoking or any kind of tobacco. 4 eat food which is less in fiber so it can be digested easily and make you hungry again. 5 instead of eating large quantities of food in single meal take small portions of food frequently.