Your diet can have an enormous influence on how long you live and your likelihood of contracting disease. In this interview, Valter Longo Ph.D., professor of gerontology and biological sciences at the University of Southern California and director of The Longevity Institute, discusses the health benefits of a fasting-mimicking diet.

The fasting-mimicking diet developed by Longo’s team is thus named because it affects important disease and aging pathways in your body, such as insulin-like growth factor 1 (IGF-1), IGFBP1, glucose and ketone bodies, in the same way water-only fasting does. Longo has done extensive research in one of my areas of passion, which is optimizing mitochondrial metabolism through dietary interventions. He’s also spent many years looking at the health effects of calorie restriction.

“I was a student of Roy Walford many years ago. Roy was one of the pioneers of calorie restriction. He was a medical doctor [who] was very interested in using diet to prevent and even treat diseases. That started back in the early ’90s.

Then I went on to turn to a more molecular understanding of what connects each ingredient, what connects each amino acid, the sugars, the fats, the type of fats, to the pathways that we were studying, particularly the pro-aging pathways. Two of them we discovered: the RAS-PKA pathway [and] TOR-S6 kinase. Both have now been shown to be central in the aging process, not just in simple organisms and mice but possibly also in humans,” Longo says.

Longo’s lab also discovered the role of the target of rapamycin (TOR) pathway in aging and in the protection of cells. (The TOR pathway itself was discovered by Michael Hall.) Understanding the impact of food on this pathway is essential for understanding how to optimize your diet.

Calorie Restriction and Longevity

You’ve probably heard that calorie restriction has been linked to longevity. However, the scientific evidence for this is still rather weak. Calorie restriction typically refers to cutting calories by 30 to 50 percent on a continuous or consistent basis. According to Longo, most of the long-term studies done on monkeys and other animals have produced questionable results. And, while some studies have found beneficial effects on mortality and diseases, others have not.

“This is why we never really focused on calorie restriction, but tried to get the benefits of calorie restriction and at the same time not the negative effects. That’s where these periodic fasting-mimicking diets come from,” Longo explains.

There’s also the practical challenge of actually applying calorie restriction, as most people simply cannot remain compliant on a general “starvation diet” for years on end.