FASTING-MIMICKING DIET: a clarion call for human nutrition research or an additional swan song for a commercial diet?

Numerous studies have reported beneficial effects for fasting in cellular and animal models, but human studies have shown conflicting results. Recently, a new diet has been introduced both in the scientific literature and in the lay media, the so-called fasting-mimicking diet. It is mainly characterized by a diet period that imitates fasting (generally 4-5 consecutive days) consisting of low or very low-calorie intake with a low or very low contribution of carbohydrates and proteins and a high fat intake. This protocol has been tested in some experimental animal models that have studied different outcomes, and in two small clinical trials that have reported some alleged beneficial effects especially on cardio-metabolic risk parameters. However, these clinical trials suffer from many limitations that require attention. The purpose of the present paper is to review the experimental and clinical studies that have investigated this particular dietary approach and to critically discuss the results.