Diet Tip: Maintaining your weight while eating what you want

I drink about 100 oz. of water a day and exercise (mostly just walking on a treadmill) for 30 minutes a day to maintain my weight. By doing these two things, I can pretty much each whatever I want and maintain my weight. I eat a lot of Mexican food! The water load may sound like a lot but I just save my styrofoam cups from fast food restaurants, which are usually 32 oz. cups and I fill them up throughout the day. One cup with ice holds about 18 oz. of water. You'll drink at least one of these during your workout, which just leaves four. During my 30 minute workout, I run as fast as I can for 30 seconds about every 4 minutes. I don't eat a lot of real fatty food, but like I said, I eat a lot of Mexican food and also quite a bit of pasta and maintain a weight of 120 lbs. and I'm 36.