Fasting for a week:
- Causes significant changes in protein levels across various organs.
- May have health benefits beyond weight loss, but only after 3 days.
- Switches energy source from glucose to fat after 2-3 days.
- Average weight loss of 5.7 kg (fat and muscle), with most fat loss sustained after 3 days of eating.
Implications:
- Provides insights into the molecular basis of fasting’s health effects.
- Paves the way for developing alternative treatments based on fasting benefits.
- Confirms historical use of fasting for specific health conditions.
My understanding is that severe shifts in calorie intake vs output can lead to lasting metabolic changes. I think the main example people point to is that all “biggest loser” contestants failed to keep their weight down even when they maintained their diets and exercise for a long period.
It’s not really metabolic per se, but hormonal. Hunger is hormone driven. If you restrict calories, you recalibrate your hormonal response to fullness and hunger.