A black plate with food between a fork and a knife that look like clock arms.
Smaller studies show that diabetics who tried intermittent fasting didn't need to use insulin.

Intermittent Fasting and Diabetes: Does It Help Insulin Levels?

Let’s shine some light on intermittent fasting (IF) for a moment. Chances are good that a friend or family member is using this tactic to lose weight and maybe even improve their health. Intermittent fasting utilizes an eating pattern that cycles between feeding and fasting. Proponents of IF state that it is not a diet – it is an eating pattern. Common fasts last for 16 hours, while feeding is in between an eight-hour period. So, when it comes to intermittent fasting and diabetes, is it beneficial, or harmful?

Why is Intermittent Fasting Used?

Is IF helpful and healthful for our bodies? Research indicates that there may be positive benefits.

A team of researchers at the University of Alabama performed a study on a small group of obese men with prediabetes. The men fed during a period of 8 to 12 hours and fasted the remainder of the day. Here are the results:

  • Lower insulin levels.
  • Improved insulin sensitivity.
  • Lower blood pressure.
  • Reduced appetite.

In a review on the science of IF in the New England Journal of Medicine, researchers believe that IF works on a molecular level.

According to Harvard Health, who summarized the study, “Fasting is evolutionarily embedded within our physiology, triggering several essential cellular functions. Flipping the switch from a fed to fasting state does more than help us burn calories and lose weight. The researchers combed through dozens of animal and human studies to explain how simple fasting improves metabolism, lowering blood sugar; lessens inflammation, which improves a range of health issues from arthritic pain to asthma; and even helps clear out toxins and damaged cells, which lowers risk for cancer and enhances brain function.”

How is Intermittent Fasting Used?

There are a variety of ways to perform IF. Some of the more common IF methods are:

  • 16/8 method: using this method, a 16-hour fast is performed. All food is consumed during an eight-hour period. This is also called the Leangains protocol.
  • Eat-stop-eat: A fast is typically performed for 24 hours, once or twice per week.
  • 5:2 diet: using this method, regular eating patterns are used five to six days per week, but the remaining days involve consuming 500 to 600 calories.

The most common and easiest fasting method is the 16/8 method.

Benefits of Intermittent Fasting and Diabetes

A very small case report reviewed three people with type 2 diabetes who used insulin to reduce their blood sugar levels. These people all fasted three times per week, and within one month they did not require any insulin. These people also noted the following benefits:

  • Improvements in BMI.
  • Reduced waist circumference.
  • Reduced HbA1c levels.

This case report is too small to make any specific conclusions on the benefits of intermittent fasting and diabetes. A larger study indicated that nearly half of people with type 2 diabetes achieved remission and were able to stop their medications. However, more research must be performed before making blanket statements on the benefits of IF and diabetes.

Risks of Intermittent Fasting and Diabetes

It is extremely important that if you decide to try IF and you have diabetes, you must discuss this with your healthcare provider.

There is a significantly increased risk of hypoglycemia, specifically for those who take insulin or oral medications, such as sulfonylureas, which cause the pancreas to make more insulin.

Some people may also notice hyperglycemia while performing IF. This could be because there is a surge of glucose from the liver after hypoglycemia occurs.

Other side effects of IF may include:

  • Bad breath, which is especially common with a low-carbohydrate diet.
  • Difficulty concentrating.
  • Low energy levels.
  • Excessive hunger.
  • Sleepiness during the day.
  • Irritability.
  • Insomnia.
  • Dehydration.

How to Perform IF Safely if You Have Diabetes

It is vital that you discuss your plan with your healthcare provider. Modifications may need to be made to your IF plan, as well as your medication plan, to reduce the risk of side effects.

During your fast, it is important to check your blood sugar frequently for hypoglycemia and hyperglycemia. It is also important that hypoglycemia be treated immediately, even at the risk of breaking your fast. Hypoglycemia can be life-threatening. Hyperglycemia can also be life-threating, especially if you have type 1 diabetes, as you can develop ketones quickly.

If you are at risk of hypoglycemia, you should always keep a form of quick-acting carbohydrates with you. Examples include juice, hard candies, fruit snacks and glucose tablets.

Finally, it is important that you find a way of eating that is consistent with your lifestyle. IF is not for everyone, and if it does not agree with you, it is okay to resume a normal eating pattern.