Considered one of the top eating and fitness trends, intermittent fasting sounds like just one more deprivation-driven eating plan that leaves you wistfully glancing at other people’s plates while you hunker down over yet another glass of water. That’s likely because of the word “fasting” right in there.
But intermittent fasting is more about strategy than starvation. It’s meant to reset your body in different ways, hopefully with fitness and nutrition changes as a result.
Like any big switchover, though, results may vary when it comes down to the individual level. What works for your friends may not work for you, or vice versa. That’s why it’s helpful to play around with variations on intermittent fasting and find what works best for you.
WHAT IS INTERMITTENT FASTING AND WHY DO IT?
Intermittent fasting doesn’t involve specific foods, but rather, a strict schedule regarding when you eat. Also called “time-restricted eating,” the tactic has been praised for its contribution to weight loss, improved body composition, decreased cravings and even athletic performance and endurance. Preliminary research also suggests it may be beneficial for glucose tolerance, hormone regulation, better muscle mass and lower body fat.
Part of its appeal is the simplicity of the effort. Unlike some other trends like “if it fits your macros” plans or keto-focused eating, there’s no calculations to intermittent fasting.
You simply eat within a certain block of time, usually a window of 8–10 hours, says nutritionist and personal trainer Jamie Logie, author of “Taking Back Your Health.” In the other big block of time — about 14–16 hours, including when you’re asleep — you don’t eat anything, not even snacks. You can drink water, coffee, tea or any other beverage that doesn’t have calories.
For example, if you like having a late dinner, you might skip breakfast and have your first meal at noon and your last meal of the day at 8 p.m., and then not eat until noon again the next day.
There are other variations as well, according to Dr. Luiza Petre, a cardiologist who practices intermittent fasting herself and advises the strategy for patients. She notes that some people do the “5:2 eating plan,” which means two nonconsecutive days of a strict 500-calorie diet, and five days of a normal, healthy food. This on-again-off-again method can be tweaked to 7:1 or 1:1, she notes, based on how someone wants to implement intermittent fasting into day-to-day life.
You can also extend your fasting time or do an occasional longer fast, adds Dr. Jason Fung, author of “The Complete Guide to Fasting.” For example, you may eat only between noon and 6 p.m. and fast the other 18 hours. Or you could do a 24-hour fast once or twice a week.
IDEAS FOR GETTING STARTED
“One of its advantages is that it may be added to any diet you are normally following,” says Fung, “including low-carb, ketogenic or Paleo. Although some people have said there are risks, those have been largely myths. Intermittent fasting has been used for millennia without difficulty.”
If you’re new to the strategy, it may be helpful to eat within the typical circadian rhythm and keep eating within daylight hours, says registered dietitian Lauren Harris-Pincus. This can be especially beneficial if you’re looking at intermittent fasting for weight-loss goals.
“We know from extensive research that those who eat breakfast have better metabolic outcomes than those who skip,” she says. “And eating at night can be detrimental to cardiometabolic health.”
The easiest way to try intermittent fasting is to do the most common variation first, advises Harris-Pincus. Determine which eight-hour block of time works best for you, and plan all your meals and snacks to fall within that time frame. Then, fast for the other 16 hours, which includes sleep.
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Fung suggests trying that for about a week or so to give your body time to adjust. After that, you’ll know better if you have to tweak your time block to some degree or if you’d prefer to switch to a different variation like the 5:2 eating plan or a similar on-off fasting schedule.
Giving yourself at least a few days — and ideally longer — every time you switch strategies is important because it allows you to see improvements in non-food areas such as more energy, deeper sleep, happier mood and better digestion. Try logging changes like these so you can track what works best for you.
Like any major eating and fitness shift, it can take time to find the perfect fit, so don’t be afraid to experiment with different options — including ditching intermittent fasting altogether if it’s simply not your groove. But if it is, you may be surprised by some of the benefits that come along with the strategy.