Raw vegetables, as opposed to animal protein, is the way to a clean, healthy digestive system. Any time you consume meats, make sure you balance them out not with breads, but with the proper veggies (broccoli, cabbage, brussel sprouts). Problems arise when you combine bread (especially white, which you should really eliminate completely) with meat, as they require different digestive enzymes. For optimal health, don't concentrate so much on the stomach as on what surrounds it - pancreas and liver. Digestive bitters and Milk Thistle are good supplements to look into.