One very large likely contributor to all the important effects of multi-day fasting or fasting-mimicking are the changes that happen to a cell signaling pathway known as the growth hormone IGF-1 axis. The IGF-1 axis is an extremely important pathway that is activated potently when we consume essential amino acids and protein but is reduced by up to 50% after just a few days of fasting in humans.

We know now from the calorie restriction field that... the restriction of calories like that can have incredible effects on diseases, diabetes particularly, but also cancer, cardiovascular diseases—really unbelievable effects.