Hello dear we have a diet which help to gain weight naturally without any side effects. There are many reason of being underweight. Improper liver functions. Endocrine imbalance (diabetes/ thyroid. IBS.Tuberculosis. Improper dietary diet. Vitamins and minerals deficiency .Eating disorders. Improper sleep .Stress. Medication Many more HOW WE TREAT UNDERWEIGHT THRU DIET. Finding and Curing the cause of underweight. Treating the deficiency and symptoms cause due to underweight. Diet to get ideal weight Before prescribing any thing ,we need some health information like Vitals, health parameter, physical activity, family history, occupation, daily routine and any many. So ,if you want to contact ,please contact us thru Lybrate.