No disrespect meant to Spin, but I disagree. Although you can't take supplements at OCS...you will be able to do so following (with exceptions). I would definitely do like farkle said and invest in a whey protein powder (you can get 5 lbs. for like $22.00 at www.dpsnutrition.net), some glutamine powder (to prevent muscle breakdown, or catabolism...take before/after workout...prior to bed), a good mutlivitamin...I use centrum performance, then some CLA, which is a fat that helps your fat metabolism stay up and your testosterone levels stay elevated as well. Those are my "Big 4" and they work well for strength and recovery. Plus, since they're all found in foods, they have no side effects (unless you aren't used to a protein shake...then you might make a couple runs to the head)! Also, hydrate and don't forget to get enough sleep...that will stop your gains. Good luck and I hope that helps.
JR