By: Andie Horowitz
Throughout quarantine, I watched my 23-year-old brother transform from a run-of-the-mill college student to a disciplined, self-proclaimed fitness king. And while he woke up early every morning and ended each day on the Peloton, he swore his newly adopted lifestyle was most powerfully changed by one factor: intermittent fasting. I was taken aback, as I had only heard the term used by my freshman year roommate, who commonly tried different diet trends. Because of this, I had dismissed the idea as just another fad — but according to my brother, it was way more than that.
With this in mind, I was interested in investigating the question: Is intermittent fasting the life changer it's hyped up to be?
Intermittent fasting was first popularized in 2012 by 'Horizon: Eat, Fast and Live Longer,' a BBC documentary that followed journalist Michael Mosley as he participated in the practice. After the story illustrated a significant improvement in health markers such as weight loss and lowered cholesterol levels, the world recognized both the legitimacy and potential of intermittent fasting.
Intermittent fasting can be practiced in multiple ways, with three dominant methods emerging as the most common: the Alternate Day Fasting, the 5:2 diet, and the 16:8 diet. While different in their technical nuances, each approach includes a general emphasis on distinct periods for eating and digesting, otherwise labeled as fasting. Alternate Day Fasting requires intense diligence week-in and week-out, as this method requires that users' fast' — aka limit food consumption to a maximum of 500-600 calories — every other day. At the same time, the rest of the week is spent eating typical amounts.
The 5:2 diet is similar but marginally less restrictive, with this approach suggesting participants fast only two days each week. On the contrary, the 16:8 diet implements a more regular schedule, consisting of a standard set 8-hour eating and 16 hour fasting period. Users are free to eat whatever they please during each regimens' allotted eating times, though a well-balanced, nutritional diet is still recommended.
Why people think it works
A near-constant eating schedule has become the norm in today's world, especially when considering factors like busy workdays and late-night munchies. We eat whenever we get a chance, with limited attention paid to the time of day. Unfortunately, and challenging to avoid, these habits can make it harder to metabolize food at a healthy rate.
The theory surrounding intermittent fasting lies in the body's natural clock and hormone production. By allocating specific times to eating, intermittent fasting allows the body to re-sync into a more natural cycle — think circadian rhythm, but for the digestive system. In doing so, metabolism can improve, leading to a host of benefits including potential weight loss, a decrease in body fat, improved heart health, and decreased chance of diabetes.
There is exciting research being done that looks good, although much of it has been done on mice. For example, one study had obese mice eat a high-fat diet on an intermittent fasting schedule. Incredibly, the mice actually lost weight. Another showed improvements in both health and lifespan due to intermittent fasting.
Although this research is promising, intermittent fasting is not recommended for everyone. Most of the studies conducted thus far sample the typical everyday dieter, not extending to those with particularly vigorous exercise regimens such as athletes or trainers. That said, there have been compelling, anecdotal reviews by athletes, such as MMA fighter Georges St-Pierre.
Although many of these benefits could be beneficial, especially for those who participate in sports, athletes should be mindful of their caloric and protein intake while practicing in intermittent fasting to maintain a healthy diet. Additionally, for those with a history of disordered eating, the nature of intermittent fasting can potentially trigger a resurgence of those unhealthy practices.
Brendan, one of our cofounders, has been 16:8 intermittent fasting for about 6 months and says he has experienced substantial benefits - everything from mid-day energy to better digestion to a decrease in body fat percentage. He says he plans to keep it up indefinitely. His only word of caution: make sure you're eating enough calories within the eating window to prevent unhealthy weight loss.
The research surrounding the topic is thorough and compelling; for many, it appears as if the regimen yields the success it claims to be so famous for. With the solid foundation for both how and why intermittent fasting works, it's hard to argue against the idea. But while the 16:8 diet seems rather feasible for everyday people, I'm still wondering how sustainable the Alternative Fasting and 5:2 diets really are. Either way, they require a lifestyle change.
To me, the mechanisms of the later two methods seem overly-restrictive. And the narrative created by a requiring a strict maximum on daily calories could lead to unintended consequences in how a person views their relationship to food. What we don't want is further contribution to an already toxic weight-loss industry. But if done correctly, one can be careful about this factor and still create a plan that is right for them. In that case, we're all-in on the safe implementation of intermittent fasting.