"Is the adage “calories in, calories out” true? The short answer is yes, but the full story is more nuanced....."From the moment food touches your tongue to the time it leaves your body, your digestive system and gut microbiome work to extract its nutrients. Enzymes in your mouth, stomach and small intestine break down food for absorption, while microbes in your large intestine digest the leftovers. More at The Conversation ➜