What Are the Pros and Cons of Intermittent Fasting? – Mass General Brigham
Food is fuel for your body. But getting the right balance of calories and nutrients can be tricky. Intermittent fasting is one approach to eating that’s gained a lot of popularity. But is it a smart strategy, or a passing fad?
“It’s not a magic cure for losing weight,” cautions Mary Hyer, RD, LDN, CCRP, a Mass General Brigham cardiac rehabilitation dietitian. Hyer works with patients at the Elfers Cardiovascular Center at Newton-Wellesley Hospital. “But the research on intermittent fasting is promising.”
So how does it work—and should you try it? Hyer shares the intermittent fasting pros, cons, and facts you should know before you start.
What is intermittent fasting?
A fast is just a stretch of time when you go without eating. Intermittent fasting is an eating plan where you alternate between eating and not eating for a certain amount of time.
How much time? That depends. “There are lots of options to choose from,” Hyer says. “But in the scientific world, you have to go at least 12 hours for it to be considered a fast.”
Time-restricted eating plans are some of the more approachable models, Hyer explains. With these plans, you eat every day but only during certain windows. You might eat all your meals and snacks between 10 a.m. and 6 p.m., then fast the other 16 hours a day. Some people choose 6-hour windows for eating, others 10 or 12.
More intense intermittent fasting plans follow the so-called 5:2 approach. You eat normally for five days a week. On the other two days, you dramatically restrict your diet, cutting calories by at least 75%. (For example, if you normally aim for 2,000 calories a day, you’d eat no more than 500 calories on fast days.) But this more extreme approach is definitely not for everyone. Always talk to a health care provider before trying any low-calorie meal plans.
Intermittent fasting: Pros and cons
Intermittent fasting has been shown to help with weight loss and improve some markers of health. But it’s not for everyone. If you’re thinking of trying a fast, consider the pros and cons.
Pros: Intermittent fasting benefits
One big thing that intermittent fasting has going for it: “It’s very easy to do,” Hyer notes. “You don’t have to track your meals or count calories. It’s something you can fit easily into your life.”
Plus, evidence shows fasting can be good for you. Scientists have done a lot of research on fasting in animals, and some in people. Those studies show a range of potential benefits, both for heart health and overall health. The benefits include:
- Weight loss
- Less inflammation
- Better brain health
- Fewer age-related diseases
- Longer life
