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No, Fasting does NOT cause loss of Strength, for the Millionth Time

Eating and Muscle Growth are two completely different things.

Dr. Jason Fung
8 min readAug 15, 2024

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Many people insist that you need to eat lots of protein to build muscle. That’s not the way our body works. It’s simple human physiology. When you eat, you store food energy (calories) either as glucose (in the form of glycogen) or fat (triglycerides). Not muscle. When you don’t eat (fasting), your body will burn stored calories from either stored glucose (glycogen) or stored body fat. Not muscle.

Eating does NOT build muscle. It is super, super obvious that the only one reliable way to build muscle is exercise. When you use your muscles to lift heavy things, it gets stronger. When you don’t use your muscles (like during bed rest or in zero gravity for astronauts), your muscles get weaker. Duh. It doesn’t particularly matter what you eat.

Let me say this again, because it’s really important. Eating does NOT build muscle, otherwise we’d be a nation of Supermen and Superwomen. Mostly people are trying to sell protein supplements and shakes. Whenever you hear somebody tell you that you need to eat protein to build muscle, run away. Very fast.

Many ‘longevity experts’ insist that you eat lots of protein to avoid age related loss of muscle — sarcopenia…

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Dr. Jason Fung
Dr. Jason Fung

Written by Dr. Jason Fung

Nephrologist. New York Times best selling author. Interest in type 2 diabetes reversal and intermittent fasting. Founder www.TheFastingMethod.com.

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