Will the digestive system weaken with inactivity?

Define inactivity. What came first, the chicken or the egg? Are you not eating? If so, the GI tract is not doing its job & the muscles surrounding the entire track may become atrophic (weaker). Digestion, absorption, and production of chemicals may not be weakened however. If inactivity came first, then a functional GI work-up is in order. By this I do not mean scoping, but a much more thorough look molecularly.