Losing weight is simply a function of calories in < calories out. With your dietary restrictions, you're going to have to figure out how to make that work, but that's what it boils down to. I find that if I eat much healthier foods (organic, whole foods, no preservatives/additives, etc.) I don't need to eat as many calories to "nourish" my body, and I can cut my calorie intake way back.

I weighed between 225 and 215 for the longest time, even while riding every day. I was "fit" but I wasn't losing weight. Once I cut back my calorie intake and increased the quality of calories I did eat, I lost 35 pounds in 3 months. I'm now down to 172 (as of this morning) and slowly still losing.