It seems each decade has its own iconic wellness fad. In the 1990s, low-fat fervor swept the nation with decadent, guilt-free dupes. The early 2000s ushered in the low-carb craze, introducing Atkins and South Beach programs. And while terms like “ancestral eating” and “plant-based” are abuzz today, there’s a surprising new front-runner: fasting.
Fasting—the simple practice of refraining from food or certain beverages for a set period—has risen in popularity. Again. Hardly a new concept, fasting has been used for religious or spiritual purposes for centuries, but modern research paints it as the secret to anti-aging. Its appeal lies in its straightforwardness: no need for special equipment, exotic foods or financial transactions.
In 2022, scientists at the University of Texas Southwestern Medical Center caused a stir when they found that reducing the total caloric intake of mice by a third caused the rodents to live 10% longer. More surprisingly, though, is that a subset of the mice—fed only during a two-hour window at night, a peak time for the nocturnal rodents—experienced a 35% increase in life span. This suggests that the timing of our meals is as crucial as their content, challenging the widely held theory that what, not when, we eat matters most.
Meg Bowman, M.S., C.N.S., L.D.N., C.H.E.S., co-founder of Nutrition Hive (nutritionhive.health), a dietary counseling service in Wilmington, believes the positive effect of fasting on the migrating motor complex (MMC) of the gut is profound. “It is basically the garbage truck for your gut,” she says, adding that MMC activity shuts down while we eat. “It takes five or six fasted hours for the MMC to complete a cycle. When people don’t get these breaks between food, you see overgrowth, you see gut dysbiosis. If you can get the gut solid, everything else kind of follows.”
At its core, the “magic” of fasting lies in its ability to trigger autophagy, a cellular recycling process that purges the old to make room for the new. “Autophagy [acts] as a cleaner for your cells—it works to take out unnecessary or damaged components, which allows the cells to perform at their highest level of function,” Bowman explains.
“For example, imagine your refrigerator after a trip to the grocery store,” she says. “At first, you’re eating all those new foods you just bought (a fed state) and don’t need to work hard to figure out how to get energy. After you’ve made all that new food, you have leftovers sitting in the fridge that you have to do something with. Inducing autophagy by fasting helps you to clean out that refrigerator by either eating your leftovers (reusing cell components in another way), or throwing out the leftovers leaving you with a clean fridge.”
Although in ancient times we fasted when primal instincts governed our appetites and availability of food guided our whims, modern information on fasting is slightly more complex. For example, the fasting frontier isn’t just about skipping meals but mastering the art of timing. Mindy Pelz, D.C., author of Fast Like a Girl, explains that abstaining for 12 to 16 hours, or intermittent fasting, allows blood sugar to decline, prompting the liver to break down fat as an alternative energy source. Autophagy “kicks in” around the 17-hour mark, but it takes at least 72 hours for stem cell production to begin. Fasters looking for anti-aging effects might consider a longer span for this reason. “Stem cells turn back the hands of time,” Pelz says. “Because they can repair all different types of cells in your body, when you get a surge of them, your body finds the tissues that have the most degeneration and heals those first.” But is longer always better? Pelz says a one-size-fits-all approach does not work.
“We need to learn as a society how to listen to our bodies,” Bowman says. “Studies show the last time we listened, in terms of hunger and fullness, was when we were toddlers. We can get back to that. …If you’re having a rough day, give [intermittent fasting] a shot, but if it’s not working for you, eat something. It’s not going to kill it. I think our culture is like, ‘You must do this five-day thing where you eat 800 calories a day.’ We don’t do a good job at finding the middle ground. There are ways to do it that aren’t so severe.”
We need to learn as a society how to listen to our bodies. Studies show the last time we listened, in terms of hunger and fullness, was when we were toddlers. We can get back to that.
Of course, as with most things, fasting is not for everyone. “[It’s] frequently contraindicated for people with mental health issues,” notes Bowman, especially those with obsessive-compulsive or anxiety disorders. “There is evidence that it [can] help, but at the same time, sometimes fasting or really changing your food in any significant way can be a little bit addictive to the brain. It becomes a compensatory behavior.”
Kathlyn Carney, M.S., M.Ed., a certified Nested health coach and yoga teacher (kathlyncarney.com) from Wilmington, highlights fasting’s positive effects on circadian rhythm—the body’s internal clock that regulates various biological processes over a 24-hour cycle, such as sleep-wake cycles, hormone release and metabolism.
“Before society advanced, people used the sun as a marker for when to wake up, when to work, when to eat and when to rest,” Carney says. She explains that aligning eating patterns with daylight hours may optimize metabolism and nutrient digestion: “This may be because our bodies have evolved to eat food and turn that food into energy when the sun is out and rest and repair when it is dark outside.” Carney also references a 2018 study by Emily Manoogian and Satchidananda Panda, Ph.D., that suggests maintaining an undisturbed circadian rhythm supported by diet could reduce the risk of chronic illness while enhancing sleep quality and metabolic function.
Lewes resident Michele Onyango, who recently celebrated her 68th birthday, has been practicing fasting since she turned 60. “It has really normalized my blood sugar. I don’t feel deprived. I’m not thinking about if I could have a sugary snack,” she reports.
Pelz explains how the body makes the switch to fat-burning mode. First, she says, we burn sugar for quick energy. “When you stop eating, your blood sugar drops. This slow decline of glucose in your blood triggers your cells to switch over to the fat-burner system. …If you have never gone longer than eight hours without food, there is a likelihood that you may never have experienced the healing benefits of [this].”
Onyango, who regularly follows the 16:8 technique (16 hours of fasting alternating with eight hours of eating), has fostered a healthy cadence with fasting but admits the practice was initially challenging. “The body doesn’t like it—at first. It took about two weeks to acclimate. Now, I’m not as hungry. In fact, I stop eating at 8 p.m. and I make myself eat at noon.” The best part, she says, is the get-up-and-go effect. “I have more energy now than ever.”
For Robin R. Hayes, M.S., R.D., C.D.C.E.S., L.D.N., founder of Nutritionally Speaking (locations in Bear, Dover and Lewes; nutspeak.com), the word disruption comes to mind. “The idea of humans creating routine or checking a box has become challenging to who we are. We accept the idea of three meals a day, because it fits how we live. But when we are so routine that our body is acclimated to it, that’s when you get into a rut. So, if you slept in on the weekend or skipped breakfast here and there, it’s not a tragedy. Your body goes, ‘Oh, good, we’re doing something different.’”
For fasting newbies, Bowman encourages a light approach. “Try some experiments and see what feels best in your body. For some people, 12 hours is a lot on their system, and there are others who can comfortably go for 16. But if you’re under high stress, getting very little sleep or your nervous system is just messed up, the last thing you want to do is a long fast. Are you super fatigued or having a ton of brain fog? If so, you might want to back off a bit and see how you feel then.”
There are also proper exit strategies. Breaking a fast successfully is as nuanced as the fast itself. Bowman recommends easing your way back into eating with foods that won’t spike blood glucose. “I wouldn’t suggest pancakes. That’s going to be a little bit of an assault on the body versus something that is higher in protein, fiber or a little bit of fat.”
The idea of humans creating routine or checking a box has become challenging to who we are. …If you skipped breakfast here and there, it’s not a tragedy. Your body goes, ‘Oh, good, we’re doing something different.’
For those who need a push to make it through their fasting window, black coffee and seltzer can be flavorful alternatives to water. Herbal tea can also offer staying power. Bowman says sipping on bone broth, while it will technically break your fast, may still be a way to support metabolic health and cellular rejuvenation through calorie restriction.
Whether your goal is to burn fat, reset the gut microbiome or sharpen mental focus, fasting can be an effective tool, but it should also be done carefully and deliberately. Do some personal research, talk to your medical providers and have a playful attitude. There is a learning curve. Hayes encourages partakers to reap the benefits but to proceed with caution. “Intermittent fasting might very well be helpful,” she says. “But you need to know what you’re doing; otherwise, it’s a loaded gun.”
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