Fasting Cancer: How Fasting and Nutritechnology Are Creating a Revolution in Cancer Prevention and Treatment

Book Title: Fasting Cancer: How Fasting and Nutritechnology Are Creating a Revolution in Cancer Prevention and Treatment

Author: Valter Longo, PhD

Publication Details: Avery, 2025, 320 pp., $32.00, hardcover

Good things happen in your body when you do not eat. Circadian code research shows that we should spend 12 to 14 hours daily fasting, also described as time-restricted eating.¹ During this fasting period, a cleanup crew is active with autophagy or recycling old cell parts. After 12 hours, we also start burning fat for energy and releasing ketone bodies that have a number of health benefits. One of those benefits is to retard the growth of cancer.

In 1931, German scientist Otto Warburg won the Nobel Prize for showing that the growth of cancer required the glycation of carbohydrates and that cancer growth is suppressed or eliminated on a ketogenic diet.² From this, the concept of starving cancer developed. The story of Otto Warburg, a Jewish scientist in Germany during the Nazi occupation, is fascinating and covered in a book by Sam Apple.³

Valter Longo, director of the Longevity Institute at the University of Southern California (USC), has used this science to lead a number of studies on how fasting may prevent and treat cancer.⁴ Longo is well-known for a longevity diet using 5 days of “fasting mimicking” with a daily intake of 500 mostly plant-based calories.⁵ In his fasting cancer studies, Longo repeats these fasting sessions every 2 weeks. Working with the cancer center at USC and one in Rome, he has had successes with a wide variety of cancers. In Fasting Cancer, Longo also presents research from other fasting cancer trials.

Because weight loss is common in patients with cancer, the idea of fasting during treatment is counterintuitive, and even resisted by many cancer-treating physicians. Some oncologists are hostile to the idea of fasting as part of cancer treatment. “Eat whatever you want” is a more common recommendation. Because sugar and carbohydrates may feed the cancer, this approach would be detrimental to the patient’s health.

Longo begins the book by giving a modern view of what cancer is and its causes, especially dietary habits that are unhealthy. He promotes a diet consisting mostly of healthy vegetables, eating meat sparingly and limiting protein. After setting the stage for this approach in the early chapters, Longo reports on successes in a variety of cancers, devoting chapters to breast cancer, gynecological cancers, prostate cancer, colorectal cancer, lung cancer, blood cancers, brain cancer, kidney cancer, and even skin cancer. Longo emphasizes that the fasting method is used along with standard cancer therapy and should not stand alone as treatment.

While cancer remission is not guaranteed from fasting, and the successes are case by case, using fasting to treat cancer should be more widely practiced based on 100 years of evidence. This book, by a respected scientist working in an academic setting, has the potential to spread this knowledge to other major cancer centers. Longo did not originate the use of fasting to treat cancer, but he may be credited with helping change the paradigm of cancer treatment.