Does Fasting slow metabolism?

This is one of the biggest fears around fasting. But science actually says, "When you start fasting, your body first uses stored carbohydrates (glycogen)". As insulin drops, it shifts to burning fat. Carb usage decreases but fat burning increases.

That’s not metabolic damage. That’s metabolic adaptation. Yes, during longer fasts BMR may reduce slightly (5–15%). But this is temporary and metabolism rebounds once you eat properly.

The real risk isn’t fasting. It’s unplanned fasting that leads to muscle loss. When structured correctly, fasting improves metabolic flexibility your body’s ability to switch between glucose and fat efficiently.

Fasting doesn’t break metabolism. Done right, it can strengthen it.