Which type of diet do they put a person on when they need to lose weight to inlist in the army?

Up to you: In general, since there are more unemployed folks around, they are not desperate to hire people who "need work." so, that means the weight loss is up to you, pre-indoctrination. Calorie restriction and increased activity are the mainstays of any diet program, and your dr can help if you need it. Good luck.

Try healthy approach: I agree with dr. Alves. There is no particular program that is used. The basics for weight loss is that calories burned must exceed calories consummed. The more effectively you are able to do this, the more quickly you can come into enlistment standards. But don't go too fast or you can become weak, lose your muscle mass & drop your metabolic rate.