Intermittent fasting: If you’re not doing it yourself, you probably know someone who is. This diet trend has been capturing headlines and the attention of people looking to shed pounds quickly for several years now.
Yet, while intermittent fasting shows benefits, new research has cast doubt on whether it’s right for everyone.
The Scary Heart Risk in the News
For example, a news release published last year after an American Heart Association meeting reported some potentially concerning findings — namely, that people who followed an 8-hour, time-restricted eating schedule, a type of intermittent fasting, had a 91% higher risk of dying from heart disease.
That’s compared to people who followed a standard schedule, eating across a range of 12 to 16 hours a day.
Ara Maranian, MD, a cardiologist at UVA Health who specializes in treating heart disease, breaks down what you should know about whether to decide if intermittent fasting is good for you or not.
What is Intermittent Fasting?
In a nutshell, intermittent fasting is following a schedule where you alternate between eating and not eating for a certain amount of time.
Although there’s lots of room for interpretation around that loose definition, most of the time, when you hear someone talking about intermittent fasting, they’re talking about time-restricted eating plans. You may only eat between the hours of 10 a.m. and 6 p.m., for example, and fast for the other hours. Or you may choose a different window that works better with your life and schedule.
There are more intense forms of intermittent fasting, too, like the 5:2 approach, where you eat normally for 5 days a week and drastically restrict your diet for the other 2.
The Benefits of Intermittent Fasting
#1 Ease
One of the biggest benefits of intermittent fasting is that it’s relatively easy to do. You simply identify your fasting window, set an alarm or choose another way to remind yourself of when to begin, and commit to following the plan. For many people, that’s a much more attractive option than constantly counting calories.
#2 Fewer Calories
Another major benefit, of course, is that people who follow an intermittent fasting plan often consume fewer calories just because they have less time to eat.
For people who struggle with their weight, Maranian says that reducing the number of calories you take in is always a good idea. You just need to make sure you’re doing it in a sustainable way. “We want people to eat balanced, healthy diets but in portion sizes that bring their weight into a healthy range and then sustain that weight,” he says.
#3 Health Benefits
So far, research has found the health benefits of intermittent fasting also include:
- Improved blood sugar
- Less inflammation
- Lower blood pressure
- Lower cholesterol
The Cons of Intermittent Fasting
#1 Fasting Can Make You Cranky
Fasting can have different effects on different people. It may not be the best option for everyone.
“If you’re prone to getting ‘hangry,’ for example, it may not be a good choice for your family and co-workers,” Maranian says.
Some people can experience headaches, trouble sleeping, and dehydration when they fast.
#2 Lack of Research
Intermittent fasting also needs more studies to confirm its benefits, Maranian continues. The study suggesting an increased risk of heart death for people who eat for less than 8 hours a day, for instance, was a retrospective study based on surveys.
“That means it should be taken with a grain of salt,” he says. “Randomized, prospective trials should be performed to confirm this. In that study, time-restricted eating did not increase death when accounting for all causes.”
#3 Fasting Isn't Healthy For Everyone
Some people shouldn’t try intermittent fasting at all. This includes:
- Kids
- Women who are pregnant
- People with diabetes
- Older adults
- People with a history of disordered eating
Find the Right Diet
With so many claims online, how do you know what works & what's healthy?
So...Is Intermittent Fasting Good for You? The Takeaway
Maranian points to studies that show alternating fasting days with non-fasting days (like the 5:2 method) has a similar effect on weight loss as simply reducing calories. Similarly, he says, there’s not a big difference between time-restricted fasting and just cutting total calories.
“Intermittent fasting can be effective for weight loss in that it reduces total caloric intake over a 24-hour period, but it’s not necessarily better than other diets that reduce calories,” he says.
Maranian advises considering time-restricted eating as one of many weight-loss strategies that can be successful if done correctly.
“If you’re interested in intermittent fasting, you should talk about it with your doctor,” he says.
