Metabolic flexibility is the capacity to match fuel oxidation to fuel availability—or switch between burning carbs and burning fat. Someone with great metabolic flexibility can burn carbs when they eat them. They can burn fat when they eat it (or when they don’t eat at all). They can switch between carbohydrate metabolism and fat metabolism with relative ease. All those people who can “eat whatever they want” most likely have excellent metabolic flexibility. So, why does it really matter, and how does it happen? Let’s get into the weeds today.

(This Mark's Daily Apple article was written by Mark Sisson, and is narrated by Tina Leaman)