This patient support community is for discussions relating to dieting,
alcohol and dieting, balanced menus,
diabetes, success stories,
exercise,
metabolism,
healthy dieting, healthy snacks, holiday tips, and nutrition. Also covered are discussions relating to specific diet plans like the South Beach Diet, Atkins Diet, Slim-Fast, Weight Watchers, Counting Calories, Fat Flush, Body for Life and others.
What do you eat on a typical day?
http://quick-help.net/Gaining-Weight-Tips
Really, though, I'd have your doctor check your thyroid levels. You might have a thyroid problem. Or you might have a really high metabolism. See a doctor. There might be many reasons. Type I diabetics lose weight I think instead of gaining, so maybe you are diabetic type I? That's the children's diabeties, but it can have a later onset, during the teen years. Diabetes can be checked by having the doctor check your blood sugar levels. Diabetes type I is usually diagnosed after people (usually kids or teenagers) start losing weight and having increased thirst and get lethargic from high sugar levels (their pancreas slowly stops making insulin).
People lose weight for so many reasons, and they generally aren't good, but you might be like my brotherinlaw who just has a high metabolism. My sister complains sometimes that he's eating their family out of house and home. HE will seriously eat 2 hamburgers, 2 or 3 hotdogs, a whole bag of potato chips, potato salad, cole slaw, and then ask what is for dessert. Doctors found nothing wrong with him. He's about 5'6" and weighs 120. Now he tries to eat more healthy, stuff like fruit and vegetables, leaner meats like chicken and fish, beans and rice and stuff that fills him up. And yes, it does cost more. Before when he couldn't afford to eat healthy, it was a bag of potato chips.
I can't say I wish I had your problem with not gaining weight. I have the opposite problem where it won't come off.