Have you tried the Lindora food products? They have a great chocolate shake; it's made with Fructose, rather than sugar, and it's only 90 calories. I usually have that for breakfast. It's a powder that you add water to - I put in less water so it's a pudding consistency, and then I add trail mix (about a 1/4 cup or less - that's 120-140 calories). It tastes great and fills me up. It also ensures that I won't buy junk food from the vending machine at work! For lunch, I usually walk to Whole Foods and get a salad at the salad bar. I keep track of the calories for whatever I put in the salad (I keep a calorie list for various foods). I also found a great salad dressing - "light Greek dressing" - it's only 60 calories in a tablespoon. (I know that sounds like a lot, but the creamy dressings are twice that!) I try to stick to about 1200-1300 calories/day.
By the time I've walked back to my office at noon, I've walked for about 30 minutes, so I get some exercise in during the day. I also work out at night, usually, for about 30 minutes doing aerobics. It's working, because my weight is slowly going down.
I hope this helps.