Dr. Jason Fung, a Canadian Nephrologist is an encyclopedic resource for the impacts of calorie restriction and fasting. While he has a couple (really good) books, the following presentation is a nice overview of his work, findings and results of therapeutic fasting:

'Therapeutic Fasting - Solving the Two-Compartment Problem' https://www.youtube.com/watch?v=tIuj-oMN-Fk