Sorbitol, a sweetener used in sugar-free gum, candy and some other diet foods may cause gas, cramps and even diarrhea in some people. Sorbitol is found naturally in apples, avocadoes and other foods, but at higher amounts may cause negative effects. Researchers at the University of California Davis observed that a high fat diet combined with certain antibiotics changes intestinal microbes that would normally help digest sorbitol, resulting in sorbitol intolerance. Authors of the study in the journal CELL say their research may add an important understanding to effects of some keto-friendly diets, which may be high in fat as well as containing sorbitol or similar sugar alcohols. It may point to ways to diagnose, prevent and treat sorbitol intolerance.