What Is Intermittent Fasting?

Intermittent fasting is an eating pattern where you cycle between periods of eating and fasting. It does not say anything about which foods to eat, but rather when you should eat them. There are several different intermittent fasting methods, all of which split the day or week into eating periods and fasting periods. Most people already “fast” every day, while they sleep. Intermittent fasting can be as simple as extending that fast a little longer. You can do this by skipping breakfast, eating your first meal at noon and your last meal at 8 pm. Then you’re technically fasting for 16 hours every day, and restricting your eating to an 8-hour eating window. This is the most popular form of intermittent fasting, known as the 16/8 method.

10 Evidence-Based Health Benefits of Intermittent Fasting

1.Can help you lose weight and visceral fat

Many of those who try intermittent fasting are doing it to lose weightGenerally speaking, intermittent fasting will make you eat fewer meals.Unless you compensate by eating much more during the other meals, you’ll end up taking in fewer calories.Additionally, intermittent fasting enhances hormone function to facilitate weight loss. Lower insulin levels, higher HGH levels, and increased amounts of norepinephrine (noradrenaline) all increase the breakdown of body fat and facilitate its use for energy.  One 2011 review also showed that intermittent fasting caused less muscle loss than continuous calorie restriction However, a 2020 randomized trial looked at people who followed the 16/8 method. In this diet, you fast for 16 hours a day and have an 8-hour window to eat. The people who fasted didn’t lose significantly more weight than the people who ate three meals a day. After testing a subset of the participants in person, the researchers also found that the people who fasted lost a significant amount of lean mass. This included lean muscle More studies are needed on the effect of fasting on muscle loss. All things considered, intermittent fasting has the potential to be an incredibly powerful weight loss tool.

2. Reduced Blood Pressure

IF may help lower high blood pressure in the short term. A study published in June 2018 in Nutrition and Healthy Aging found 16:8 significantly decreased the systolic blood pressure among the 23 study participants. The link has been shown in both animal and human studies, according to a review published in March 2019 in  Nutrients. And, an October 2019 study published in the European Journal of Nutrition found IF led to even greater reductions in systolic blood pressure than another diet that didn’t involve defined eating times.Having a healthy blood pressure is important — unhealthy levels can increase your risk for heart disease, stroke, and kidney disease.

But so far the research shows these blood pressure benefits last only while IF is practiced. Once the diet ended and people returned to eating as normal, researchers found the blood pressure readings returned to their initial levels.

3. Improves Brain Function

Dr. Gottfried says IF may improve mental acuity and concentration. And there’s some early research to support that idea: A study on rats published in February 2018 in Experimental Biology and Medicine found it may help protect against the decline in memory that comes with age. According to Johns Hopkins Health Review, IF can improve connections in the brain’s hippocampus and also protect against amyloid plaques, which are found in patients with Alzheimer’s. This study was done only in animals, though, so it’s still unclear whether the benefit holds true for humans.

4. Lower Risk of Cardiovascular Issues

Per the aforementioned Nutrients study, when insulin levels fall, so does the risk of dangerous cardiovascular events, such as congestive heart failure, which is important for patients with type 2 diabetes because they are two to four times more likely to die from heart disease than adults without diabetes, according to the American Heart Association. The Nutrients study noted that while there aren’t human studies to confirm the benefit, observational studies have shown IF may deliver both cardiovascular and metabolic benefits. Lowden suspects that changes to metabolic parameters, such as lower levels of triglycerides and a decrease in blood sugar levels, are the result of losing weight and would be achieved no matter how the weight was lost, whether through IF or a low-carb diet, for example.

5. Disease prevention

Supporters of intermittent fasting suggest that it can prevent several conditions and diseases, including:

• type 2 diabetes
• heart conditions
• some cancers
• neurodegenerative diseases

However, the research in this area remains limited.

A 2014 review reports that intermittent fasting shows promise as an alternative to traditional calorie restriction for type 2 diabetes risk reduction and weight loss in people who have overweight or obesity.

The researchers caution, however, that more research is necessary before they can reach reliable conclusions. A 2018 study indicates that in addition to weight loss, an 8-hour eating window may help reduce blood pressure in adults with obesity. Other studiesTrusted Source report that intermittent fasting reduces fasting glucose by 3–6% in those with prediabetes, although it has no effect on healthy individuals. It may also decrease fasting insulin by 11–57% after 3 to 24 weeks of intermittent fasting. Time-restricted fasting, such as the 16:8 method, may also protect learning and memory and slow down diseases that affect the brain. A 2017 annual review notes that animal research has indicated that this form of fasting reduces the risk of nonalcoholic fatty liver disease and cancer.

6. Lower cholesterol

One of the reasons fasting can lead to weight loss is because you’re eating during daytime hours, e.g., when your body naturally wants to consume calories.

“When we eat according to our circadian rhythm—meaning we consume energy during our active hours of the day when the sun is up and eat less in the evening—we metabolize our food better and see improvements in blood sugar and lipids including cholesterol and triglycerides,” explains Harris-Pincus. 5:2 fasting, in particular, may improve cholesterol levels. As WH previously reported, a 2018 study showed that people who followed a 5:2 diet had a lower risk of heart disease than people who dieted by counting calories.

7. Better sleep

The science here is still emerging, but researchers have been studying the effects of food intake on sleep for years. Some research has shown that eating late at night can disrupt sleep or cause sleep disturbances, though sample sizes are usually pretty small.

There’s also not a lot of direct evidence that fasting—instead of eating—before the nighttime hours can have the opposite effect, but it does make sense. Plus, one study from 2003 found that a week of fasting resulted in less sleep arousals (though only 15 people were tracked and that study is fairly old, obviously).

8. Improved Gut Health 

Another intermittent fasting benefit is that it directly influences the gut microbiome, helping it do a better job at preventing inflammatory toxins from leaking into your bloodstream.

9. Can Help You Live Longer 

All these health benefits work together for the ultimate benefit: a longer life! Thanks to intermittent fasting, you can significantly improve your health, helping you live longer and happier.

10. Repairing Cells

When you are involved in fasting, your body regulates cellular repair processes called autophagy. In this process, the cells digest and remove dysfunctional proteins built inside the cells.