Extending longevity with the Fasting-Mimicking Diet (FMD)

© Dr. Michael D. Jacobson, D.O. Do not reproduce this article without permission.

Editor’s note: This information was published in the July 2019 issue of Heartfelt Magazine, CHM’s monthly magazine that provides CHM membership-related tips and tricks, medical advice from doctors, testimonies from CHM members, and more. Please refer to the CHM Guidelines and applicable web pages for the most up-to-date information regarding CHM membership, sharing eligibility, and ministry news

Editor’s note: To read parts 1 to 3 of this article series, see the April, May and June issues of Heartfelt Magazine.

The Blue Zones are five world regions with populations reaching 100 years of age at a rate 10 times higher than the U.S. average. The lifestyles of these centenarians are characterized by activity, healthy eating, transcendent purpose and strong family and community relationships.

Dr. Valter Longo of the University of Southern California’s (USC) Longevity Institute also noticed that centenarians have lower blood levels of Insulin-like Growth Factor-1 (IGF-1), which plays a significant role in cell renewal and regeneration, a process known as autophagy.

Autophagy can be activated by exercise and fasting. The problem—at least according to some researchers—is that the type of fasting that fully activates autophagy (see last month’s article) must exceed 24 or even 30 hours. It can be assumed, though, that this length of time without food is very difficult, if not unbearable, for the majority of those who would otherwise consider fasting.

Consequently, Dr. Longo and other researchers wondered if it’s possible to experience the benefits of prolonged fasting without a complete water-only, 30-hour fast. (Note: I have found some disagreement in the literature as to how long an individual must fast to achieve health benefits. Some articles I reviewed indicate that there is a benefit to fasts as short as 12 hours, which are typical of an overnight interval.)

The answer to the researchers’ question apparently is yes: the key is to restrict protein and sugar rather than simply restricting calories. Protein stimulates IGF-1, so reducing protein intake downregulates the body’s key nutrient-sensing pathways, thus triggering autophagy to activate cellular regeneration and rejuvenation.

To test their hypothesis, researchers recruited 100 volunteers and randomly assigned them to either eat their normal diet or follow what they called the “Fasting-Mimicking Diet” (FMD) for three one-month cycles.

Each cycle consisted of a five-day period in which those on the FMD only consumed food from a proprietary diet provided by the Longevity Institute, followed by their usual diet for the rest of the month. The FMD five-day food supply was packaged and labeled, came in a box, and consisted of vegetable-based soups, energy bars and drinks, tea, snacks and supplements with essential fatty acids.

On the first day, calories were limited to around 1,100, while the next four days restricted calories to 714. The composition of the food was only about 10 percent protein; the rest was evenly divided between fats and carbohydrates (about 45 percent each). After the three monthly cycles were complete, the control group was also offered the program and the majority of them accepted.

Note: this program can be found at prolonfmd.com. It’s expensive (between $250 and $300 for a five-day box) and this article is not an endorsement of the product or program.


Of those who were tested with the FMD diet, 94 percent were compliant. Though side effects of fatigue, headache and weakness were common, individuals considered them to be mild and they diminished with each progressive cycle.

The FMD demonstrated numerous beneficial effects. Not surprisingly, the average statistics for the experimental group showed a reduction of:

  • weight by an average of five pounds, mostly from belly fat (preferred weight loss area)
  • waist circumference by 1 inch (while preserving lean muscle mass)
  • IGF-1 levels (which are associated with a number of common diseases such as diabetes, cardiovascular disease, hypertension and arthritis)
  • blood pressure (both systolic and diastolic)
  • total and LDL (“bad”) cholesterol
  • high-sensitivity C-reactive protein (an inflammation marker)


What didn’t drop were stem cell markers, which are essential precursors to virtually every healthy cell type in the body.

Furthermore, individuals with the worst health benefited most from the diet. And, perhaps most surprisingly, the vast majority of improvements were still present nearly four months after the last five-day cycle was completed.

To summarize, there are numerous types of “fasting diets” gaining popularity:

  • Calorie restriction (as a daily habit) or intermittent fasting (such as the “5:2 diet,” in which participants restrict calories to 25 percent their usual intake for two out of every seven days)
  • Time-restricted (usually 12 to 14 hours, such as no eating between dinner and breakfast)
  • Prolonged fasting (usually multi-day, water-only and supervised by a physician in a fasting center or as an inpatient service)
  • The Fasting-Mimicking Diet (FMD), which seeks to attain all the benefits of a prolonged fast, but while allowing 700 to 1,000 calories per day
  • for at least three five-day per month cycles.


Virtually all of them cause at least some degree of weight loss as well as a reduction in cholesterol. The degree of fasting likely correlates directly with the degree of autophagy: the processes in which cells “cleanse,” rejuvenate and regenerate health.


  1. Khan, Joel. “The Longevity Diet.” Lecture, Medical-Dental-Legal Update, South Lake Tahoe, February 1, 2019. References:
  2. Wei, M., S. Brandhorst, M. Shelehchi, H. Mirzaei, C. W. Cheng, J. Budniak, S. Groshen, W. J. Mack, E. Guen, S. Di Biase, P. Cohen, T. E. Morgan, T. Dorff, K. Hong, A. Michalsen, A. Laviano, and V. D. Longo. 2017. “Fasting-mimicking diet and markers/risk factors for aging, diabetes, cancer, and cardiovascular disease.” Science Translational Medicine 9 (377). doi: 10.1126/scitranslmed.aai8700.
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