The new year is upon us and if you’re anything like 60% of Americans, you’re planning on rebooting your life by improving your diet, exercising more and losing weight—the three most popular resolutions since the tradition started.
Happen to be one of these? Then chances are you’re considering intermittent fasting (IF)—an increasingly popular form of restricted eating in which one abstains from eating for a specific period of time.
As the top-trending diet search on Google in 2019—and raved about by everyone from Jennifer Aniston to Gisele—intermittent fasting generally falls into three categories: the 5:2,or OMAD diet, in which you eat regularly five days a week but consume only one meal a day (500 calories for women, 600 calories for men) twice a week; the 16:8, where you eat within an 8-hour window each day and fast for 16 hours; and “Eat-Stop-Eat,” a method popularized by fitness buff Brad Pilon in which you fast for 24 hours twice a week.
As registered dietician Jessica Cordin puts it, intermittent fasting—or “IF” to its followers—“tells you when to eat, but not necessarily what to eat.” Celebrities to athletes are, well, eating it right up, in part because it’s been linked to weight loss.
Is intermittent fasting safe?
Sound intriguing? For sure—especially since a brand new study published in The New England Journal of Medicine suggests that intermittent fasting may improve longevity, boost heart health, reduce blood pressure, and, yes, result in weight loss. Study author Mark Mattson—a professor of neuroscience at John Hopkins University—says “time-feeding,” as it’s also called, can enhance cellular health by triggering “metabolic switching:” a process in which cells use up their fuel stores and convert fat to energy. (Not to be confused with the keto diet, which radically reduces carbohydrates and sends the body into ketosis.
What’s more, a previous study, co-authored by Mattson, showed that IF can “increase resistance to stress by optimizing brain function and neuroplasticity, or the brain’s ability to adapt to develop throughout one’s life,” CNN reports. Other studies still suggest that it may slow the effects of aging, while clinical trials have demonstrated that it can decrease insulin resistance. Carolyn Brown, MS, RD, phrases it all differently, saying “Limiting your eating hours a bit can let your body stop focusing on digesting and instead spend some time on de-stressing, anti-inflammation, memory, immunity and so much more.”
The potential benefits of fasting may sound promising, but diving into a fast without knowledge or caution can backfire mightily, leaving even the most virtuous among us prone to binging when eating resumes, or resulting in health complications and discomfort (Mindy Kaling referred to it as “16: hate” for a reason.) Here are seven ways to ensure you’re fasting as safely as possible:
1. Ease into it
You wouldn’t run a full marathon if you’ve only just started jogging a mile or two per week—and the same holds true for fasting. Jumping into a 24 hour fast when you seldom skip a meal will render the whole experience miserable—and put you that much closer to feasting when the fast ends.
Instead, work up to it. Undertake shorter fasts and gradually extend the amount of time between eating. There’s a reason why the 16:8 form of intermittent fasting is the most popular, of course: It’s less of a test on your brain, body, and willpower.
2. Be mindful of what you consume when you do eat
Choosing to fast intermittently shouldn’t translate into downing pepperoni pizza and chocolate croissants when you do eat. Indeed, doing so may backfire and lead to weight gain (to say nothing of the headaches, bloating, and gastrointestinal distress that may come with it). Rather, pile your plate with whole foods—fruit, vegetables, legumes, and organic, humanely-raised meat, eggs, and fish—and use mindfulness to tap into your body’s inner hunger cues: Pause between forkfuls, take small bites, and ask yourself if you’re really hungry or just bored, thirsty, or emotional (which, in sum, is eating mindlessly).
3. Don’t fast for long
Yes, Mattson has been practicing intermittent fasting for 30 years, but for most of us, this is simply unsustainable. Work schedules, social commitments, needing to refuel after a workout—even maintaining a healthy partnership—can easily conflict with the rules of time-feeding. More importantly, fasting for long periods of time will deprive you of the vitamins, minerals and other nutrients you need to function properly—period.
As WebMD reports, prolonged fasting “can lead to anemia, a weakened immune system, liver and kidney problems, and irregular heartbeat” as well as vitamin and mineral deficiencies, muscle breakdown, and diarrhea. And the longer you stay on a fast—or repeatedly go on fasts—the more severe these problems become. (No “perfect” body is worth such pain.) Jennifer Wider, RD, advises having an exit strategy to reacquaint yourself with your body’s natural hunger (and satiation) prompts; she also recommends working with a dietician to come up with a more manageable, long-term eating plan.
4. Adjust your workouts
As alluring as fasting may be, the fact is you’ll be depriving your body of the nutrients it needs to operate, potentially resulting in decreased focus, irritability (talk about hangry), fatigue, nervousness, dizziness and, naturally, diminished energy. Thinking you can hit up your favorite power weight lifting aerobic class after not eating for 24 hours straight could wreak havoc on your biological system, crank up your production of cortisol, and leave you exhausted. In short, if you’re intent on fasting, your workouts will have to be adjusted. Walking and gentle yoga will be far more palatable—and less likely to push you into such a ravenous state that you’ll be robbing your children’s stash of holiday candy.
5. Hydrate
Medical News Today reports that fasting commonly leads to dehydration. Why? Your body isn’t getting any fluids from food. Ensure you’re drinking plenty of water, or go for sparking mineral water: the carbonation might help ease the heartburn that often accompanies fasting.
6. Take a multivitamin
Taking a multivitamin is always a good idea, in that it gives you a boost of nutrients you may not be getting enough of through diet alone. It’s even more imperative when you’re fasting. For a potent blend that’ll naturally support your energy levels, go for Vitacost Synergy Multivitamin. Supplying 22 essential vitamins and minerals—including vitamin D, folate and zinc—this superstar product also contains green team CoQ10 and other health-supportive antioxidants.
7. Consult with your physician before you decide anything
Whether you’re twenty-five or fifty, going without food for anysignificant amount of time presents potential problems, including muscle aches and mood changes. And while children, pregnant and lactating women, diabetics, and the elderly should stay far, far away from the whole idea of fasting, you too—even if you don’t fall into these groups—should get your doctor’s approval before abstaining. People with a history of eating disorders, for example, should not attempt intermittent fasting. As fitness and nutrition expert JJ Virgin wrote in The Huffington Post, “The ‘anything goes’ mentality some experts permit during the feeding state could lead someone to overeat, creating guilt, shame, and other problems that only become worse over time. For someone with emotional or psychological eating disorders, intermittent fasting could become a convenient crutch to amplify these issues.” Be honest with your doctor—and be prepared if he or she recommends seeing a registered dietician for a smarter, more sustainable, and healthier strategy instead.
