Dear sir, I am around 49 kg male (working in pharma manufacturing since past 4 years) & my age is 30 years, height 5ft 4inch. I know I am undeweight. Vegeterian since 12 years. What can be probable cause? what should be my standard weight? I want to gain weight, please advice. My marriage is scheduled in next 1-2 yrs, but I am reluctant to marry due to such a less weight. Also, advice what test can be done to diagnose if I have any diseases.