After two weeks of intermittent fasting, certain muscle signaling molecules changed—GSK became more active and mTOR less active—but these didn’t translate into changes in how the body used sugar or...

Skipping meals intermittently for two weeks didn’t change how the body uses sugar, fat, or muscle protein in healthy, lean people—even when their insulin levels were raised.

If healthy young people don't eat for a week, their muscles might switch how they burn fuel during exercise—using less sugar—which could make it harder to keep up with endurance activities.

If healthy young people don’t eat for a week, their muscles lose half their stored energy from carbs, but they can still work just as hard during intense exercise.

Fasting for a week doesn't seem to change a key energy sensor in young healthy people's muscles, which suggests it might not be what causes muscle breakdown during fasting.

When healthy adults don’t eat for 3.5 days, their bodies start breaking down fat for energy—even though the usual fat-burning hormones and blood sugar levels stay pretty much the same.