Is there any connection between stomach disorders and weight?

Absolutely. Remember - everything that happens in your body starts with the food you eat, digest, and absorb. This provides the basic building blocks for everything in your body. If yo don't digest well (lack of acid or digestive enzymes), or you don't absorb well, or have a metabolic disorder underlying utilization of nutrients or detoxification, then your body starts to suffer. This can cause weight issues.