18 years old, I cant gain weight, im enlisting in the United States Marine Core, the last time I went to MEPS I could NOT swear in due to being underweight, they would not give me a waiver for my weight. My metabolism is very high, I can not put on weight to save my life, I am currently taking weight gainers and working out 5 times a week but still nothing is working, I've been doing this for the last few months... Any suggestions on how I can put on a solid 15lbs? I don't care if its fat or muscle cause it will be burned off/turned to muscle in boot camp. Been chasing this goal since I was a little kid and want to get it going already, but just can not put on weight on. If anyone could help that would be awesome! Thanks!