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.

~ Christopher Damman, from Is weight loss as simple as calories in, calories out? In the end, it’s your gut microbes and leftovers that make your calories count

That’s about the greatest summary I’ve ever read. The rest of the article is good too. Definitely not too long, and worth the read.

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