Hard to fix
The odor from intestinal gas comes brom the breakdown of nutrients that you do not absorb, but feed various germs in your gut.
They feed on the excess and create methane gas and other odors that depend on the germ and item consumed. Beano and Lactaid are two OTC products in the US that help some. Keep a food diary to see which ones make u gassy/then avoid them is a simple plan.