Hello, i'm unable to gain weight my bmi was 15.9 now. Since many years i'm under weight and my body type is ectomorph. My weight right now is 55 kg with 6.1 feet height. I consulted general physician he gave few medication it helped for few months .sometimes I feel like heavy stomach after eating some amount of food then after I consulted gastroenterologist he examined my stomach with few tests everything was normal. He suggested few medication for digestion it helped. But i'm still under weight and now. I didn't understand which doctor I need to consult for help.