Starting with your tongue and ending with your colon, “it’s an amazingly complex system,” says Chris South, M.D., a gastroenterologist at Gastro Health, in Ohio.

In this case, high levels of hydrogen and methane indicate a lot of what FoodMarble calls fermentation – what's given off when your digestive system and your gut microbes are, well, digesting.

Cycling Cycling has various benefits for digestion. Physical exercise can boost the number of healthy gut bacteria and promote the digestive system’s regular functioning.