Calculateur de changement métabolique de jeûne

The metabolic switch is the point during fasting when your body shifts from using glucose (from food and glycogen stores) to primarily burning fat and producing ketone bodies for energy. This typically happens between 12 and 16 hours into a fast, depending on body composition and activity level.

Yes. Exercise during your fast depletes glycogen stores faster, which can accelerate the switch by 2-4 hours. Eating a low-carb meal before fasting also helps, as there is less glycogen to deplete. Staying active (even light walking) makes a noticeable difference.

Light to moderate exercise during a fast is generally safe and can speed up fat burning. Walking, yoga, or light cardio work well. Avoid intense strength training while fasted if you are new to fasting. Stay hydrated and listen to your body.

Common signs include reduced hunger, increased mental clarity, a metallic or fruity taste in the mouth, slightly fruity breath, increased thirst, and sustained energy without the usual dips. You can also measure ketones with urine strips or a blood ketone meter.