How can I make my body use its fat stores?? HELP!!?

Thanks for taking the time to read my question. I already know that one of the ways to make my body use its fat stores for energy is to exercise. Ok, i'm trying to lose weight, I weigh 196 and i'm 5'5 and want to get down to a 140. I want to know how I can make my body use its fat stores for energy without constantly munching on veggies and fruits to keep my metabolism humming. It is almost impossible for me to take out a baggie of fruits and veggies every couple of hours because I'm not in a suitable environment to do that most of the day (i'm at a construction site). It's more convenient for me to have 3 meals a day (healthy meals with lows carbs, low fat, and low calories and high in protein). Is there a way to trick my body not to go into starvation mode and still keep the metabolism going and still have my 3 square meals?? Please give me a thorough answer with all the possibilities. :) Oh, and I've begun to do 45 mins. on the elliptical the morning and afternoon everyday. Please help me if you can, I'm willing to work hard to lose weight and I just want to have all of the correct information to start. Thanks in advance:)