I have found that the only way to maintain my weight is to eat under 100g of carbs per day, and under 50g I tend to lose weight. I can eat significantly more in calories, so long as it's whole foods.

If you haven't looked at Dr. Hooshmand's 4 F's diet for RSD, it is something to try. I find it's made a major difference in my energy level and stomach pain. I'm also a fan of Marksdailyapple.com which is a Paleo food plan. I've written about it at length previously, but if you'd like more info, please let me know.