When the December 2019 New England Journal of Medicine publishes a review article on “Effects of Intermittent Fasting on Health, Aging, and Disease,” you know that there is significant scientific interest in fasting for therapeutic purposes. But it is unlikely that is news to you, as I’m sure, like me, that many patients are asking you about or have already started some sort of fasting regime. Intermittent fasting (IF) involves extended periods where an individual doesn’t consume calories. The most common form is daily time-restricted feeding, essentially a prolonged overnight fast, where a person will eat in a restricted window, typically six to eight hours. Other intermittent fasting methods include alternate-day fasting, where food is cut out or restricted every other day; a five to two schedule, where one 500 to 700 calorie meal is eaten two days per week, and what is termed a fasting-mimicking diet (FMD), where a low calorie, low carbohydrate diet is followed for five days, and that is cycled monthly or quarterly. There is recent exciting research, older studies, as well as just cultural or religious traditions that all suggest significant benefits of fasting. These benefits include improvements in mental or cognitive performance, physical performance, cardiovascular health, diabetes, and obesity. While the mechanisms are not all worked out, what appears to happen is that a mild ketosis ensues during IF. This metabolic switch in the fuel source of the body and brain likely increases metabolic ‘flexibility’ and the efficiency of energy use. Additionally, other mechanisms suggest that IF makes the body more resistant to stress and inflammation. I tell my patients that part of the benefit is just giving the body a longer chance to remove and repair damaged molecules. One of the advantages is that for many people (with some supervision), IF can be worked into their schedules relatively easily, and it is a very low (to no) cost option. We’ve created a short overview of IF options, as well as an instruction sheet that you can easily fill out to guide your patients in the program you think is right for them. For much more information, I encourage you to consider our Annual Conference at the end of May, where you’ll hear about the various aspects of IF from some world-renowned experts in the field.

To access the IFM Clinical Practice Toolkit, log in to your account, select “My Education” from the left-hand side, then click on the IFM Toolkit tile. To find this toolkit document, search for “Intermittent Fasting” within the toolkit.