Hi, Thank you for posting your query in healthcaremagic.com This is Dr. Swarnava dattagupta answering your query. I understand your concern. see basically if you are underweight, you need to take healthy food like lots of fruits and vegetables, dietary fibers, less fat and fast food. also take small frequent meals and two heavy meals a day. take multivitamin syrup to increase appetite. also provide your height and weight so that i can calculate your BMI and tell you how much weight to gain, so you can get a diet chart done by a dietitian. Hope i have answered your question. If you have any further questions i will be happy to help. Regards