First off the Corps has actually raised their standards. You can actually be in shape and pass the PFT but look fat and nasty and that (after all sorts of paper work and programs) can get you kicked out. But to initially enlist you need to be able to at the very minimum complete 3 pull ups, complete a 1.5 mile run in a specified time, and do as many crunches as possible in 2 minutes. If you are overweight a recruiter will work with you to get you into shape and into the Corps' standards. Once at bootcamp if you are still overweight as mentioned before you will be placed into a PCP or Physical Conditioning Platoon. I've never heard of these "fat farms"