When I think about eating, I think about the yummy taste of food and the pleasure of feeling satiated. But after attending a Harvard Medical School conference on Gut Health, Microbiota and Probiotics Throughout the Lifespan, I now realize I am not feeding my body but rather the 100 trillion bacteria that live in my gut – my microbiome. We have about 3 to 4.5 pounds of microbes that outnumber human cells by a factor of 10 to 1.