Gaining weight ONLY makes you heavier...it has nothing to do with your height. Eat more, eat less...you will still be the exact height you are supposed to be.It's in your genetics. Guys are not done growing until they're 21-22, so relax and be patient. If you are meant to grow more, you have lots of time left.aining weight ONLY makes you heavier...it has nothing to do with your height. Eat more, eat less...you will still be the exact height you are supposed to be.