I have been using a form of periodic fasting called a fasting mimicking diet (FMD) in my clinic with my patients, which has some pretty great benefits (similar to those from fasting). Here are some general and brain-specific data on the FMD and why you might be interested in trying it, plus how to take part in this eating plan. During the five days of restricted calories, exercise and alcohol are prohibited 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 requires eating whole olives (something to note if you dislike olives). There are even provocative data suggesting that combining this FMD with cancer chemotherapy may lead to improved success and fewer side effects3. While much more research is needed before we can make those definite claims, the data we do have sure looks promising. In old mice, FMD cycles also promoted brain growth (hippocampal neurogenesis), which would be a nice thing to have happen in humans! Researchers were able to demonstrate improved cognitive performance4. Overall, these preliminary data are encouraging. It seems the best brains may result from the least calories, at least for five days a month. As mentioned, the program provides three meals a day, with about 1,100 calories for the first day and around 800 calories from days two to five. In terms of how long you should do the FMD, the specific research states to use it five days in a row, then repeating that cycle two more times a month apart. So, to match the research, it’s a 3 month program. After that, Longo has said you can repeat the Prolon FMD monthly as often as you like. For most, a few times a year to capture the benefits is reasonable. I advise my patients that if they want to achieve the published results, they might want to do three cycles chosen at times that they do not have conflicting events, like weddings. Although not studied, a few patients of mine have done it back to back over 10 days, but not at my recommendation. While those patients did fine, it’s always best to follow the guidelines on the website and research. After three consecutive months, many of my patients choose to do the program monthly or every other month for long-term health optimization. If you’re interested in trying this diet out for yourself, consult your primary care physician and keep these tips in mind before embarking on your FMD journey. Want to learn more from Joel Kahn? Check out the first-ever functional nutrition training, where he teaches classes on heart health and veganism. A cutting-edge nutrition deep dive taught by 20+ top health & wellness experts
