i don't know which is weirder, humans losing weight by eating no-cal sweeteners or chimps avoiding malaria by eating dirt.
sorbitol, in addition to being a common no-cal sweetener, is a laxative. people who eat lots of it don't digest their food very efficiently and end up losing lots of weight. the only down-side is the chronic diarrhea. that and, as with any drastic weight-loss scheme, the dangers of malnutrition and development of mental or physical disorders, such as bulimia and anorexia.
chimps eating dirt, on the other hand, is now understood to be an effective way of protecting themselves against malaria. certain type of soil combined with specific plants and digested together leads to lower chances of getting malaria. hopefully, the animal behavioral scientists are in communication with medical scientists, so they can capitalize on this information (the good kind of capitalization, though. not the bad kind). maybe they'll finally be able to come up with an anti-malaria treatment that works without the side-effects of current options. dirt + plant. how hard could it be?