The Best Type of Fasting for Blood Sugar Control

Here’s something that might surprise you…

When it comes to managing diabetes, the food you don’t eat could be just as important as the food you do eat.

Cutting back on calories doesn’t just support better blood sugar control. Fasting improves insulin sensitivity and kickstarts fat burning.

For people with diabetes, these changes can be so powerful they may even trigger remission.

If you’ve ever looked into fasting, you’ve probably felt overwhelmed by the sheer number of options.

And honestly, until recently, we didn’t have a clear answer on which method worked best for diabetes.

But new research finally put these fasting methods to the test—head-to-head—to see which one comes out on top.

Researchers recruited 90 people with diabetes and had them try three different fasting methods for 16 weeks.

Here’s what they tested:

1. Intermittent energy restriction. This method follows a “feast or famine” approach. You alternate between days of normal eating and periods of strict calorie restriction. Some people alternate between fasting and eating every other day. Others prefer eating normally for five days, then fasting for two.
2. Time-restricted eating. This is what most people picture when they hear the term “intermittent fasting.” You eat all of your food within a specific window each day—such as eating only between 8 AM and 6 PM and fasting for the other 14 hours. In this study, people had a 10-hour eating window.
3. Continuous energy restriction. This is the most traditional fasting approach where you simply eat fewer calories every single day—typically 15 to 60 percent below your normal daily energy requirements.

Each group consumed the same total number of calories per week. The only difference was the timing and pattern of when they ate them.

All three methods improved blood sugar levels, which is fantastic news. But one approach clearly stood out from the crowd: intermittent energy restriction.

Participants on the “feast or famine” plan saw the biggest improvements in:

• Lower fasting blood glucose
• Better insulin sensitivity (meaning their bodies used insulin more effectively)
• Reduced triglycerides

In the end all three of these fasting methods showed real benefits for blood sugar control. That’s the good news. Even better? You don’t have to choose the “winning” method if it doesn’t feel right for you.

The most important thing is finding an approach that fits your life and feels sustainable. Because at the end of the day, the one that works best for you is the one you’ll actually be able to stick with.

P.S. Two-week “Summer Snack Prescription” protects your heart.

View Sources

Zhang, Comparing the effects of intermittent energy restriction (IER), time-restricted eating (TRE) and continuous energy restriction (CER) in managing type 2 diabetes with obesity, presented Sunday, 7.13 at ENDO 2025, the Endocrine Society’s annual meeting in San Francisco, Calif.