Odds are you've heard about fasting. Defined as "abstinence from eating," it is something you may have tried now and then. I observe Yom Kippur ceremonies where I do not eat for about 25 hours once a year. Beyond the spiritual aspects of fasting, the potential medical benefits have increasingly been substantiated in animal and medical research projects.
The interest in fasting has grown since The Fast Diet was published in England and gained quite a following. That program consists of decreasing calories to 500 or 600 calories a day for two days a week and has helped many people lose weight and reverse lifestyle diseases like adult diabetes. The new kid on the block, which is actually not so new, is the fasting mimicking diet (FMD). This is the evolution of decades of pioneering work on longevity by Dr. Valter Longo and his team at the University of South California. Dr. Longo is recognized as a leading expert on longevity (if not the expert) and has done great work in describing the basic biochemical pathways by which cells age. I recently completed my second month of the FMD and have started many patients on it, and here's why:
The basics of a fasting mimicking diet.
The FMD program was patented by Dr. Longo after years of basic and preliminary research in yeast and animal models. The diet in humans decreases calories to 1,100 on the first day and then to around 800 the next four days for five days overall. The nutrients are key and include plant-based whole foods like nuts, olives, teas, and soup mixes that are 80 percent fat, 10 percent protein, and 10 percent carbohydrate. During the five days of restricted calories, exercise and alcohol are out and coffee is limited to zero or one cup a day. The program is also rich in nuts—so it's not appropriate for those with a nut allergy—and it also requires eating whole olives so a few more of you are out if you hate olives.
I experienced weight loss and increased energy.
My experience with the FMD over the past two months has been remarkable. I found it simple, tasty, and filling. I was a bit hungry on day one—the day with the most calories—but felt absolutely energized and clear of mind on days two through five. I didn’t even feel that I needed to eat all the food provided. There was a sense of freedom from not wasting time considering whether that slice of pizza, that beer, or that chia smoothie were on the menu. They were simply not allowed and it was liberating and energizing. I slept well, worked efficiently, and was satiated. It was remarkable that I lost 5 pounds each time I did the plan in the five days allotted without being "hangry" or tired. The weight loss has largely been maintained as I prepare to do my third month—which is the genius of the FMD versus actual fasting.
The science behind my success.
What is so special about the FMD? The science. After years of experimenting with FMD in animal models and showing its benefits on metabolism and lifespan, Dr. Longo’s team analyzed the effects in a human clinical trial that was published earlier this year. One hundred healthy subjects participated in this study; half of them followed a Prolon FMD five days a month for three months and the other half ate their usual diet. Profound differences were seen in terms of weight loss, visceral fat loss, drops in blood pressure, blood sugar, blood cholesterol, and markers of inflammation in the FMD group.
Even more profound was a drop in insulin-like growth factor 1 (IGF-1)—which is a biomarker for cancer growth—and an increase in stem cell production, which is a marker for regeneration of cells. In fact, the Prolon FMD program is marketed by Dr. Longo’s teams at USC as a program that promotes regenerative and rejuvenating changes, which is unique from all other data published for fasting programs. There are even provocative data suggesting that combining this FMD with cancer chemotherapy may lead to improved success and fewer side effects.
What I tell my patients about a fasting diet.
I advise my patients that if they want to achieve the published results, they will need to do three cycles. I am about to begin my third cycle and am looking forward to it. After three consecutive months I am confident some patients will choose to do the program monthly or every other month for long-term health optimization. I plan to continue the diet long term as the energy and weight loss I have observed has been so simple and something I want to maintain.
In my nearly 30 years of practicing cardiology and preventive medicine, I view the Prolon FMD as one of the greatest examples of translating years of peer-reviewed science—starting in yeast, then mice, and now humans—into a plan that almost anyone can adopt and benefit from. I thank Dr. Longo and his team who have set up this fasting program to benefit research programs at USC, and not for their own gain. In my opinion, the FMD is the best fasting approach and is the one most supported by scientific studies.