Are you drinking too much while you are eating? I find that if I drink while I eat it will cause some problems, or just eating too fast and not chewing. If you are feeling any stress it will cause some GI issues and it could make your digestion off as well. Coffee, tea can also cause stomach issues especially when they change your stomach acidity. Coconut milk is also a problem for some folks.
"If man made it, don't eat it" - Jack Lallane
People say I am on a "crazy" diet. What is so crazy about eating veggies, fruits, seafood and organ meats? Just because I don't eat whole wheat and processed food doesn't make my diet "crazy". Maybe everyone else with a SAD are the "crazy" ones for putting that junk in their system.