Intermittent fasting means fasting and eating at specific intervals. It allows the body to burn fat and utilize the fat stored in the body to be used as energy.
Editor's note: This article was originally published on July 24, 2020. It has since been updated.
Intermittent fasting (IF) is a diet that doesn't really restrict a person from eating any particular food types, like carbohydrates, starch, or fat. Instead, it says that people should restrict eating into a certain window. There are many benefits to fasting over a standard diet that tells up to eat low carbohydrates or low-fat foods. "The research so far proves the benefits of IF to the extent that it is worthwhile as a method to lose weight, manage your blood sugar, and slow down the aging process," Dr. Sara Gottfried, of Berkeley, California, author of The Hormone Cure, The Hormone Reset Diet, and Brain Body Diet tells Everyday Health.
However, not everyone agrees with her. Some experts see it as a fad and there are conflicting results from various studies, as per Dr. Elizabeth Lowden, a bariatric endocrinologist at the Northwestern Medicine Metabolic Health and Surgical Weight Loss Center at Delnor Hospital in Geneva, Illinois. “For every study that shows there's no change, there are some studies that show maybe there is improvement,” she said.
There are multiple ways of doing this such as 16/8, 5:2, alternate day, 24 hours fast. But what do these mean? According to Cleveland Clinic, 16/8 or 14/10 refers to the time interval spent fasting and eating. For instance, 16 and 8, respectively, refer to the number of hours you fast and eat. The same applies to 14 and 10. But, 5:2 is different since here it means that you eat normally for five days and on two days you restrict calorie intake to 500 calories.
Alternate day fasting is self-explanatory, such as every alternate day, you eat only 500 calories in a day. The 24 hours fasting means not eating anything for a full day. This can be done once or twice a week.
“If you want to give IF a try, be prepared to figure out what works best for you,” says registered dietitian Anna Taylor. “It might take some trial and error first," she added. She also pointed out that, "Weight loss is never a one-size-fits-all approach. IF may be sustainable for some people, while others find that this approach just isn’t for them."
Here are the benefits of doing intermittent fasting:
A study published in the Journal of the Academy of Nutrition and Dietetics shows that there's a chance that any form of IF will help people lose weight. Researchers had analyzed data from 13 studies and found that on average weight loss ranged from 1.3% for a two-week trial to 8% in eight weeks. However, there aren't any long term studies available on this and it's not sure how sustainable this method of losing weight is in the long term. IF might help people who don't have time to do meal planning for other diets like keto or paleo, said Dr. Lowden to Everyday Health.
Those who have diabetes can benefit from IF by stabilizing blood sugar levels by resetting insulin. When we restrict calories it can improve insulin resistance, which is a marker of type 2 diabetes, according to a study published in April 2019 in Nutrients. With IF, insulin levels fall and that can reduce the risk of type 2 diabetes. However, this should be done by consulting your general physician. They might prescribe supplements for electrolyte imbalance that IF might cause, as per Cleveland Clinic. "So whenever we prescribe certain diets, including a very low calorie diet and protein-sparing modified fast diet, these require medical supervision. We check blood tests monthly and prescribe potassium supplementation to prevent electrolyte imbalance from occurring," Cardiologist and endocrinologist Dr. Dennis Bruemmer says.
Dr. Bruemmer says that there are many benefits to fasting for short periods but it's not safe for everyone. According to Cleveland Clinic, research shows that fasting helps reduce blood pressure, cholesterol, and control diabetes as well as reduce weight. "Four of the major risks for heart disease are high blood pressure and cholesterol, diabetes and weight, so there’s a secondary impact," Dr. Bruemmer said, adding, "If we reduce those, we can reduce the risk of heart disease."
Studies on animals have shown that IF combined with general calorie restriction can reduce inflammation. So, researchers wanted to see if it was the same for humans too. The authors of a study published in Nutrition Research studied 50 participants during Ramadan, the Muslim holiday that involves fasting from sunrise to sunset. They are allowed to eat at night. The study found that pro-inflammatory markers were lower than usual while the participants were fasting. It also showed reduced blood pressure, body weight, and body fat.
A very specific study published in the journal Obesity found that alternate-day fasting along with endurance exercise helped lower Low-density lipoprotein (LDL) cholesterol in obese humans. They found that along with body weight, waist circumference decreased and lean mass was retained. While LDL reduced, high-density lipoprotein (HDL) cholesterol, which is good cholesterol, increased but only for those who did IF and worked out.
Disclaimer: Fasting isn't for everyone. If you are unsure if fasting is right for you, you might want to