The gut is like a highway junction to every part of the body. The mucosal lining of the gastrointestinal tract (GIT) gives direct access to the blood stream which carries nutrients, oxygen, toxins, waste products, and inflammatory markers to the whole body. So when there is trouble in the gut, you can have health issues throughout your body.
When I was younger, I read something that Cindy Crawford said that has always stuck with me: "I'm not going to let anyone twist my arm and shove a cookie in my mouth". I'm sure most people have experienced that well-meaning (or not so much, but that's another blog) relative or friend who wants you to eat their 'special' cookies, casserole, or other sweet or high calorie treat.