- Intermittent fasting is a popular weight-loss diet among celebs, but so far research hasn’t definitively proved that it produces better results than eating regular meals.
- People who do intermittent fasting will restrict when or how much they can eat in a given period of time, like only eating within an eight-hour window each day.
- If you’re interested in trying intermittent fasting, get the best benefit by cutting out late-night snacking. It’ll help you eat more purposefully and get more sleep.
Intermittent fasting is a hot topic in nutrition and weight loss lately (everyone from Hoda Kotb to Jennifer Aniston has tried it), but the concept itself isn’t new. In fact, temporarily going without eating or drinking stems from the practices of many major world religions and cultures. But intermittent fasting or “IF” — a trend gaining major traction among celebrities (Terry Crews! Jimmy Kimmel! Hugh Jackman!) — does things a bit differently for purported health, weight, and cognitive benefits.
While limiting your meal times can make your eating more purposeful, intermittent fasting is not a fit for everyone. Read on before you decide to start skipping out on snacks.
What is intermittent fasting?
Intermittent fasting generally describes a simple concept: You can eat pretty much whatever you want, but only during a specific period of time. There are few common schedules that IF proponents follow, according to the Journal of the Academy of Nutrition and Dietetics:
Time-restricted fasting: This schedule, which includes the popular 16:8 method, has you fasting for about 16 hours per day and eating within an eight-hour window. Most people do this by starting their fast at night, skipping breakfast, and eating their first meal around lunchtime. That gives them another seven or so hours to feed themselves until tomorrow.
Modified fasting: This option, commonly known as the 5:2 diet, allows you to eat about 25% of your recommended calorie needs on two fasting days each week and eat without restriction on the other five days.
Alternate fasting: In this less regimented style, you switch between periods of consuming zero-calorie beverages and actual eating. Some fans follow a high-fat or ketogenic diet on their days off from fasting. The fasts can end after less than 12 hours, while others can stretch as long as a full week! The Eat-Stop-Eat method, for example, calls for a 24-hour fast once or twice a week.
Does intermittent fasting work for weight loss?
Currently, there are a few claims but not much by the way of science in favor of long-term fasting for health or weight loss. Alternate-day fasting did not help people lose more weight or keep weight off longer than people who simply restricted daily calories, according to a 2017 study published in the Journal of the American Medical Association.
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The other bad news for fasting fans? LDL or “bad” cholesterol increased in the alternate fasting day group compared to control groups in a 2016 trial. Other risk indicators stayed the same across groups on this trial and other similar ones.
But a new scholarly review, which examined previously published research on the effects of fasting diets in both humans and animals, suggests that regularly abstaining from food may aid those struggling to manage their weight in the long term. Published in the December 2019 issue of The New England Journal of Medicine, the review suggests that IF could help dieters lower their blood pressure naturally and may even have an impact on lifespan. The authors behind the new research only considered evidence linked to 16:8 time-restricted plans as well as 5:2 intermittent fasting. Like other limited studies conducted on animals, this review suggested that fasting may reduce insulin production and overall sugar uptake in fat cells, which could potentially lower one’s risk of chronic disease.
According to Mark Mattson, Ph.D., a professor of neuroscience at Johns Hopkins University and one of the review’s authors, early research has been limited by the fact that fasting isn’t the norm for most Americans. But new evidence may help health experts explore the benefits of fasting for those who may be struggling to lose weight — as well as those diagnosed with cancer, diabetes, or cardiovascular conditions, according to a new pilot study conducted on humans published in the journal Cell Metabolism in December.
Is intermittent fasting safe long term?
Intermittent fasting plans have the potential to backfire tremendously — especially if your goal is to lose weight. Fasting can lead to nausea, dehydration, and even weight gain over time. There hasn’t been enough definitive research that has effectively looked at the long-term effects of fasting on metabolism. You may also eat more than you thought you would during your days or times of “feasting” too. In his review, Mattson advises that anyone attempting to fast should gradually increase the duration and frequency of their fasts over longer periods of time — and that physicians should closely monitor your progress.
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Eating real, nutrient-dense foods on a consistent basis fuels us physically, mentally, and emotionally. So if intermittent fasting works for you, go for it! But if it makes you feel anxious, depressed, or isolated in any way, it may not be the best plan for you personally.
Plus, I’d be remiss to mention who should absolutely not dabble in this eating style: Anyone who’s previously struggled with an eating disorder or experienced disordered eating behaviors, or if you’re immunocompromised, pregnant, lactating, or on insulin, oral hypoglycemic, or food-metabolizing medications. No matter who you are: Always check with your doctor before starting any new diet plan — especially one that includes fasting!
While some research tells us that there may be potential benefits for certain dieters, if severe food restrictions provoke any anxiety, then just don’t do it. There’s no clear-cut reason to opt out of meals, so stick with consistent eating strategies that work best for you — without any shame or guilt that extreme behaviors can stir up in so many of us.
Is intermittent fasting good for you?
What I like about intermittent fasting is that there may be benefits for some people to prolong (realistically) the time they go without food as it relates to sleep and caloric intake.
More purposeful eating: The biggest advantage of intermittent fasting stems from the fact many of us eat based on the scenario, not hunger levels. (Raise your hand if you’ve ever gone to the movies after dinner and suddenly wanted popcorn.) Through IF, you’re limiting when you’re allowed to eat, meaning you cut back on habit-driven snacking you may not have been aware of. Say you’re a person who loves to graze during The Bachelor; if you’re “fasting” post 8 p.m., you’ve automatically cut out munching opportunities — and subsequently, calories.
Better sleep habits: If your fasts are time-restricted, the lack of late-night snacking alone could help you go to bed earlier — a crucial component to any weight-loss plan. Getting seven hours of sleep per night has been linked to weight management, reduced risk of chronic disease, and improved metabolism. Plus, a July 2019 study published in the International Journal of Obesity found that overweight individuals who were actively dieting and getting at least seven hours of sleep were able to lose more weight compared to those who were not.
Smarter food choices: Frequently choosing what and when to eat during a given day can leave us susceptible to making snap decisions that ultimately leave us dissatisfied — either immediately or when done consistently over time. But if you know you’ve only got a certain amount of time to eat, you may make smarter choices when you do. Simplifying and structuring the whole “what should I have for a snack?” scenario is a benefit many fasters appreciate.
How do you start intermittent fasting?
If you’re considering IF, I’d encourage you to start small and simple: Experiment with an “early bird special” for dinner. Close your kitchen once you’re finished, aim to get more sleep overnight, and eat a full breakfast at your usual time tomorrow. Making this one change is an aspect of intermittent fasting we can all get behind.
