But our ancestors who fasted only lived till 20 even with perfect sanitary conditions, healthcare, shelter, weather, no other predators, and not incomparable stress levels. And even though we became the most able and thriving species on planet by far and reduced our gut size to better fuel our brain by eating this diet and fasting.
Btw, even better than fasting is being on 30% caloric deficit. One of the few things we know that increases longevity. Fasting makes that easier ofc.