Eli5 How did the morbidly obese guy(Angus Barbieri) who fasted for one year not lose all of his lean body mass(muscles)? Does the body actually work to preserve muscle mass and not break it down when fasting as a morbidly obese person?
In: 41
Yes, your body *absolutely* works to preserve lean muscle mass. This is absolutely crucial, because some of your organs (like your heart) are composed of muscle.
When you fast, the first thing your body will use for energy is glucose (sugar). Since your body only stores small amounts of glucose, this will be used up quickly – within a few days. At that point, your body switches to *ketosis*, which means that it gets its energy from fat stores.
In fact, this is exactly why we store fat in the first place – to give our bodies a source of energy when we’re fasting. Periods for fasting were common in hunter-gatherer days, simply because we couldn’t always find food. If our bodies immediately switched to using protein, we would have gone extinct.
Latest Answers