Switzerland's Nestle, the world's largest food company, wants to tune up your guts.

Last weekend, it hosted global experts in Playa del Carmen, Mexico for a three-day workshop on the intestinal microbiome to discuss how trillions of bacteria living in the digestive system can impact everything from obesity to depression.

One attendee was Emeran Mayer, a gastroenterologist at the University of California, Los Angeles, whose family ran a German confectionery business, giving him a unique perspective on Nestle's ambitions.