Twice-monthly health columns are by a practicing cardiologist, clinical professor at Wayne State University School of Medicine and founder of the Kahn Center for Cardiac Longevity in Bingham Farms. He's an author and has appeared on national TV, including "Dr. Oz" and "The Doctors Show."
By Dr. Joel Kahn
For hundreds of thousands of years, humanity lacked access to the abundant food we do today. Our ancestors ate during the day, consumed their last meal before dusk and fasted until after sunrise.
Today we eat more frequently, often choosing unhealthful foods and mindlessly snacking while sedentary. This modern lifestyle of overconsumption and inactivity has contributed to a growing number of Americans (over 73%) being overweight or obese. To enjoy better health, and and more years of it, we need significant lifestyle shifts.
Identifying weight loss as a goal is easy, but achieving it can be quite difficult. Decades of mixed nutrition information have contributed to Americans moving from one diet to the next, often experiencing short-term weight loss before gaining it all back. Sustained weight loss can only come from everyday behaviorial change, not a yo-yo diet. Fasting can be a beneficial and simple solution to help support a sustainable, healthy lifestyle.
Fasting has become a leading diet in the United States, with an estimated 12 percent of American adults incorporating fasts into their lives. Intermittent fasting (IF) is any form of fasting that lasts 12 hours up to two days. When fasting for longer than two days (and done routinely, up to once per month), it's called periodic fasting (PF).
I will discuss the benefits of each below.
I recommend an approach called Time Restricted Eating (TRE), which lets an individual designate the number of hours each day for eating and then fast the rest of the day. A 12-hour TRE pattern is quite popular and the one I most frequently suggest.
Here's what a 12-hour fast looks like: Say you finish your last meal at 7 pm., you fast until the next morning at 7 a.m.
I recommend a 12-hour fast for a few key reasons. First, it is easy to incorporate into your day. The majority of the fast is performed while sleeping. Second, it aligns with the natural patterns of your circadian rhythm. In 2017, the Nobel Prize in Physiology and Medicine was awarded to the discovery of the body’s biological clock.
This research suggests that organs benefit from a period of rest, the same way your brain and muscles rest when you sleep. A 12-hour TRE supports this process. Finally, it can support weight loss. Setting a cutoff point after dinner helps build a mindful practice around eating and can prevent late-night snacking of empty calories that will be stored as fat.
A longer fast several times per year may be warranted in patients seeking weight loss, plus deeper benefits such as support of metabolic health and cellular rejuvenation.
The Nobel Prize of Medicine in 2016 was awarded to researchers who studied a process called autophagy, the clean-up and renewal process of our cells. Most experts believe our cells undergo autophagy beginning two to three days into a fast, though it does depend on the person’s metabolic rate, exercise level and Body Mass Index (BMI). Once you enter a second day of fasting, cells start to break down their worn-out internal structures to survive. This cellular renewal is thought to contribute to health and longevity.
Fasting with Food
Fasting with food sounds like an oxymoron, but it’s actually possible. Dr. Valter Longo, a leading researcher in the field of nutrition and aging from the University of Southern California’s Longevity Institute, developed a program with a combination of foods with a specific mix of nutrients that could be consumed without kicking the body out of a fasting state. We call this a fasting-mimicking diet (FMD).
With FMD, it’s now possible to follow both IF and PF without foregoing all food during the fasting window. This can be incredibly helpful for those who want to reap the benefits of a fast but struggle with hunger.
FMD research has given rise to over 371 patents and the creation of at least two products: Fast Bar and ProLon. Fast Bar is an intermittent fasting bar that can help extend a fast by providing a mix of nutrients that doesn't spike glucose levels. It can be helpful for those on IF who want to extend their overnight fast till noon by consuming a bar in the morning.
ProLon is a five-day meal program that uses a precise blend of plant-based nutrients that can be consumed without taking the body out of a fasted state. The clinical studies on ProLon completed to date show that three consecutive cycles confer the benefits of weight loss, fat loss, cellular rejuvenation and metabolic support. ProLon can be a great solution for those who want to try a PF.
I recommend patients combine IF and PF for maximum benefits. Observing a daily 12-hour fasting window, in addition to incorporating a five-day FMD three times a year can help support weight loss, metabolic health, and healthy aging.
Doing so with the assistance of Fast Bar and ProLon can help make the fast more feasible for those who struggle with foregoing all food.