Hi. i am 25 years old. i eat a lot i but i don't gain weight. whatshould i do?

High metabolism: Unless you are under weight, consider yourself lucky. Some people are gentically blessed with a high metabolism like yourself, and others are not, ..And they gain weight more readily if they eat like you. See a dr. And get an eval, like thyroid testing to be safe and assue you do not have any significant medical conditions. Best wishes.

Enjoy while able: You are fortunate to have a metabolism that keeps you from gaining weight or you are active enough that you burn as much as you take in for calories. Either way you are lucky. However, slender people still can get atherosclerosis, so eating a healthy diet is still necessary. If you want help to know how, read: 'food for life' and 'eat right, live longer' or 'eat to live'.

Calories count: It's simply a matter of calories taken in vs calories burned. If you eat a lot, you're probably burning a lot of calories. If you are under ideal weight, increase your total daily calories with healthy food choices.