Go pick up this book: A Week in the Zone
It's like $8 and Barnes and Noble. It's an extremely high level view of the Zone diet. It's a really light read and you can get the gist of the program quickly. The Zone itself gets criticized for being too hard (weighing and measuring food, etc.), and too generic, but this book doesn't even get into the weighing and measuring part, (or portion size much at all per individual) but it does get you into a good mindset on what types of foods to eat, etc.
At a super-high level, it's really just about eating the right kinds of foods and eating appropriate quantities, spread throughout the day. The zone claims that there is an optimal food ratio (40:30:30 of carbs (veggies/fruits), protein and fat) that causes the optimal metabolic response (insulin reaction) in the body. It makes sense, but I'm no bio-chemist.
I've been an active crossfitter for about two years. I'm still getting huge results in strength and stamina, but after a certain point, I stopped losing any more weight, because I hadn't addressed my diet. Back at the end of June, my CF box started a 12-week zone challenge. I'm about 5 weeks in and have dropped 6lbs, and more importantly 5% bf. (down from 24 to 19... I was really in denial, I guess, I was shocked when I found out I was at 24% to begin with... talk about denial!!! I knew I could stand to drop a few lbs, but no way did I think I was over 20%) I've been setting personal bests on all of my workouts for the last few weeks, and have had tons of energy, so the results aren't just on the scale.
There are a lot of critics of the Zone, and I agree with a lot of them, but it's a great start and will at least change your mindset about fuel... errr, food. If you really want to go off the deep end, listen to a few podcasts from Robb Wolf
and look into Paleo... Now that is hard core, but will get you crazy results.
It seems like it's a lot more religion than science, but if you just try to learn as much as you can, and experiment and find what works for you, you'll do great. Find something that is healthy and sustainable.
One tip I like is only shop on the outside ring of the grocery store, don't go down any aisles.... the fresh produce, meats, etc. that you really need to be eating are around the outer ring, the processed, sugary, fatty crap is in the middle aisles!
Good luck man! Find someone to commit to doing it with you, peer pressure and accountability can work wonders!