Carbs...
Carbs aren't evil, but there are different kinds of carbs and some are more beneficial than others. Fruits and vegetables have carbs and they are helpful during weight loss. Grains and starches aren't helpful when losing weight because they fill you up but don't give you satiety for as long, especially if you are prone to blood sugar issues. My post-op diet forbids grains for six months post surgery and that's okay with me. I know that personally I can't eat grains and feel well - my body just doesn't handle them well.