Pros and Cons of Intermittent Fasting for Diabetes

Health Writer

You may have heard of a trend in dieting called intermittent fasting and read that it may help control type 2 diabetes. But is it really safe for all diabetics? And what are the pros and cons? Learn more about the evidence behind intermittent fasting diets for managing type 2 diabetes.

What is intermittent fasting?

Intermittent fasting restricts caloric intake during certain times. One popular version is the 5:2 diet. This means you eat normally for five days (2,500 calories for men, 2,000 for women) and fast for two non-consecutive days, limiting your caloric intake to 500 calories in a 24-hour period on fasting days. Another version is the 16:8 diet, where you eat within an eight-hour window each day, for example, you might eat only between 10 AM and 6 PM or you might eat from 12 Noon to 8 PM. You choose the time frame that works best for your schedule. You don’t take in any calories during the remaining 16 hours of the day. The theory is that your body will burn more fat during fasting and help you lose weight. As with any diet, the goal is to develop healthy eating habits so that not only do you lose weight during the diet but that you maintain a healthy weight after.

There are both benefits and disadvantages to this type of diet.

The Pros

  • Intermittent fasting may improve body weight, fasting blood glucose and postprandial variability in people with diabetes type 2 according to a study completed in 2017.
  • It is a simple and accessible dietary intervention that is easy to implement and improves glycemic control according to a study completed in 2017
  • Intermittent fasting may be easier to stick with for some people. You don’t have to constantly restrict calories, count calories or deny yourself foods you enjoy. Intermittent fasting seems to have many of the same benefits of dieting through caloric restriction according to Harvard Health.
  • In a study involving diabetic mice, a few months of intermittent fasting cured the diabetes. The mice lost weight but the diet also seemed to reboot the pancreas, so that it started making insulin again according to a study in the journal Cell.
  • Studies in animals have shown that intermittent fasting may reduce  cancer risk and slow the aging process according to a report on Elsevier.
  • It may activate cellular mechanisms that help boost immune function and reduce inflammation associated with chronic disease according to Harvard Health. Losing excess body fat can improve metabolic profile and lower cardiovascular risk.
  • In a study involving 100 people who went through periodic fasting for 30-day cycles, 25 unrestricted eating days and five days of fasting, there were improvements in blood sugar levels with no harmful effects after three full cycles.

The Cons

  • Intermittent fasting isn’t for everyone. There is a high dropout rate. According to Harvard Health, 38 percent of participants in a study that were assigned to intermittent fasting stopped the program.
  • There may be a danger of indulging on unhealthy foods on eating days, therefore, you won’t reduce your caloric intake and may even increase it over a week’s time
  • Many of the studies showing the benefits of intermittent fasting are not supported by long-term research and many were the result of testing on animals, not on humans, according to an article in US News and World Report.
  • Intermittent fasting may cause problems because your body doesn’t have food for fuel. During fasting days, it uses fats and proteins. This means your body is burning more fat, but it also means you are losing muscle. Burning protein will also slow your metabolism, which can making losing weight more difficult in the long run according to Cedric X. Bryant, PhD in an article in US News and World Report.
  • Not enough research has been done to determine the optimal fasting regimen, including the length of the fasting interval, the number of fasting days per week, the degree of energy restriction needed on fasting days and recommendations for dietary behavior on non-fasting days according to a study published in the Journal of the Academy of Nutrition and Dietetics.
  • While the majority of people don’t seem to have any adverse effects of fasting, some people might experience constipation, headaches, and hunger pangs according to Dr. Jason Fung.

Who should not fast

While there is some evidence that some people with diabetes type 2 may benefit from intermittent fasting, it isn’t always a good choice. Skipping meals and limiting calories can be dangerous for some people with diabetes according to Harvard Health.

In addition, there are some groups of people who should not fast:

  • Women who are pregnant or lactating
  • People with diseases related to malnutrition
  • People with liver or kidney insufficiency
  • Children

Always talk to your doctor before beginning a diet program. If you have diabetes, especially if you are on any diabetic medications, you should check with your doctor before fasting. Some diabetic medications can lead to severe hypoglycemia when fasting according to Dr. Jason Fung.

See more helpful articles:

Your First 9 Steps Toward Managing Your Diabetes

The Stigma of Type 2 Diabetes

How Exercise Helps Control Diabetes

12 Ways to Lose Weight and Manage Your Diabetes

10 Superfoods for Type 2 Diabetes