Why have I failed to put on weight?

Dear Doctor; I want to know why I have failed to put on weight yet I have a good job, I eat well and I have the basics of life. I am a 33-year-old man but I only weigh 58kg. I find this very annoying because many times I meet old students who have put on weight and they make me look like a kid. What can I do to put on some weight. Peter, Kigali. Dear Peter; The weight of an individual depends not on the age but height as well. Then there are other factors like level of physical activity, kind of diet taken and genetic factors as well. Thyroid disorders like a hyperactive thyroid, uncontrolled diabetes mellitus, depression, excess work, physical or mental stress are other conditions which can prevent weight gain. To gain weigh try to make a regular schedule for meals and take some healthy snacks in between meals. Try to take food which is healthy and rich in protein and carbohydrates(unless diabetic) . Avoid overeating as that would not contribute to weight gain but can be harmful. Muscle building exercises help to increase muscle mass and also increase body weight. Let the weight increase gradually over time. It is also good to get tests done for hyperthyroidism and diabetes to exclude a medical problem for prevention of weight gain. If any of these conditions is present, it is treatable.