You might look at the types of carbs you're consuming. Stay away from processed carbs, and favor whole foods (whole grains, vegetables, bean, soy, etc.). Also,avoid flour products and go for the more whole grains (ie: instead of "corn flake" type breakfast cereal that is made from corn flour, choose oatmeal, which is made from rolled oats). The Physicians Committee for Responsible Medicine has a couple of books with guidelines for losing weight (or not gaining weight) using vegan foods. I know when I ate this way I was leaner than I am now (but I don't really have the discipline for it at the moment).