Is Intermittent Fasting Safe for People With Type 2 Diabetes?
Updated on September 17, 2026
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Fasting is hardly new. People have been doing it for religious reasons since ancient times. But fasting for weight loss is a relatively recent phenomenon that has become increasingly popular, in part because it seems to work for some people.
Research has shown that periodic sessions of intermittent fasting (IF), in which a person limits their meals to a certain window of time, with a fixed period of eating little or nothing, can boost weight loss, reduce waist circumference, and lower blood pressure, blood sugar, and triglycerides.
Given that maintaining weight, blood pressure, blood sugar, and triglycerides at healthy levels is important for people with type 2 diabetes, intermittent fasting is worth exploring if you have the condition and struggle with keeping them in check. Still, there are factors to consider before giving it a try.
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What Is Intermittent Fasting, and How Is It Done?
Even if you’ve never tried intermittent fasting, you’ve likely fasted before without even thinking about it. Fasting is often required for blood tests, medical procedures, or surgery, for example.
“When you are fasting, you naturally get fewer overall calories,” says Vandana Sheth, RDN, CDCES, a dietitian and nutritionist who specializes in diabetes management in private practice in Torrance, California. “The fasting state also causes an increase in growth hormone levels, increase in norepinephrine, and decrease in insulin levels. All these factors of intermittent fasting help with weight loss.”
There are different ways to do intermittent fasting, including eating only during a certain time period, or restricting calories on certain days of the week and eating normally on other days, among others. The most common intermittent fasting diets consist of 16- or 14-hour daily fasts.
Consult your care team first, including a dietitian who specializes in diabetes, before trying it. Whatever plan you choose should be tailored to your lifestyle, type 2 diabetes treatment regimen, and your personal nutritional needs.
Potential Benefit of Intermittent Fasting for Type 2 Diabetes: It May Boost Weight Loss
Dietitians and scientists had previously thought of intermittent fasting as a negative practice, so there isn’t a wealth of high-quality clinical research on how it may affect people with type 2 diabetes, says Jason Fung, MD, a nephrologist in Toronto and a coauthor of The Complete Guide to Fasting: Heal Your Body Through Intermittent, Alternate-Day, and Extended Fasting. But attitudes have begun to change, and some newer studies suggest the approach may have benefits, including for people with type 2 diabetes.
For example, one small study found that intermittent fasting lowered insulin resistance in 13 adults with type 2 diabetes. Insulin is a hormone that helps shuttle glucose (sugar) out of the bloodstream; people with type 2 diabetes are resistant to insulin, which results in higher blood sugar levels.
In addition, a review of research included several studies that found intermittent fasting reduced fasting glucose levels, weight, and fasting blood sugar levels in people with type 2 diabetes. Despite the results of these studies, additional research needs to be conducted to see whether intermittent fasting is safe for people with type 2 diabetes as a whole, the authors wrote.
Potential Drawback of Intermittent Fasting: It May Harm Blood Sugar Control
On the other hand, some experts say that intermittent fasting carries risks, especially for people who need to keep their blood sugar levels stable. For starters, intermittent fasting can result in hypoglycemia, not to mention issues such as fatigue.
Time-restricted eating and other forms of intermittent fasting may also cause people to make poor dietary choices, which can have the opposite effect on their waistline and blood sugar. If you haven’t eaten for hours, you may be more inclined to reach for a carb-heavy pastry or plate of pasta, for instance.
“Blood sugar management can be a real concern with intermittent fasting for people with type 2 diabetes,” Sheth says. “That’s why it’s important to discuss intermittent fasting with your physician, monitor your blood sugar closely, and know that your medications may need to be adjusted as well.” Your dietitian or a certified diabetes educator can guide and support you through this process,” she says.
A plan that severely restricts a person’s calories or asks them to skip meals can be hard to stick with long term, too, says Ruth S. Pupo, CDCES, who practices at Adventist Health White Memorial in Los Angeles.
Another risk of intermittent fasting for people with diabetes is hypoglycemia, or low blood sugar. One study found hypoglycemia, but only in participants taking sulfonylureas or insulin; the number of episodes was comparable in the group that fasted and in the group that didn’t fast (control group). In another study included in the same review, hypoglycemia occurred only in a participant in the control group.
Another review, however, found that fasting participants in one study faced a significant increase in severe hypoglycemic episodes, particularly those taking sulfonylureas or insulin. This complication can be life threatening, so it’s important to take precautions to prevent it. People who take these medications may not be candidates for an intermittent fasting diet or will need to adjust their treatment regimens and glucose monitoring with the advise of a physician before starting to fast.
Certain people, such as those who are pregnant or breastfeeding or have an underlying disease or medical condition, should also avoid intermittent fasting, Pupo says. “Anytime you have a higher demand for more nutrition, you don’t want to do a fast,” she says. People who are pregnant or breastfeeding require extra calories for themselves and their babies, Pupo says, and fasting can cause them to run out of glucose for energy and instead burn fat and muscle.
What’s more, if a pregnant person overproduces ketones (a compound that is produced when the body uses fat for fuel), studies on animals suggest the effect can be harmful to both the parent and the fetus. Intermittent fasting may also not be safe for older people with type 2 diabetes who have other health conditions. They should speak with their doctor before changing their diet.
Some people with diabetes also run the risk of developing diabetic ketoacidosis, or DKA. This arises when your body doesn’t have enough insulin to move blood sugar into your cells for use as energy. When that happens, your liver responds by producing too many ketones, which can build up in the body, damaging the kidneys and causing brain swelling, Pupo says. DKA may even lead to a diabetic coma or death, she says.
Research has shown that there may be a link between intermittent fasting, used in conjunction with a keto diet, and DKA.
Regardless of whether you have diabetes, cutting out meals or restricting entire food groups can cause nutritional deficiencies. Without proper nutrition, particularly protein, there’s also a risk for muscle mass loss. “When you really deprive the body of nutrients, your body not only breaks down fat but muscle as well,” Pupo says.
Steps to Take Before You Try the Popular Diet Plan
Here are a few things to keep in mind before trying intermittent fasting.
Talk to your doctor. Your doctor can help you come up with a safe approach and adjust any of your medications as needed. People on insulin should be particularly careful: If you’re on it and restrict your eating, you may be at a greater risk of low blood sugar, which can lead to dizziness and confusion, as well as symptoms that can lead to life-threatening complications such as seizures or loss of consciousness. If left untreated in people with diabetes, low blood sugar (hypoglycemia) can be fatal.
Find a plan that works for you. Plans for intermittent fasting vary. There are those that restrict calories two or three days a week or limit eating to certain times of the day. Stricter plans include fasting for up to 36 hours at a time twice a week, though the latter isn’t typically recommended for people with type 2 diabetes, according to Sheth. The key is to find a plan that you can stick with long term.
Be prepared for side effects. It’s common to have headaches, cramps, constipation, or diarrhea, at least initially. But, says Dr. Fung, “If you’re feeling very unwell, stop. You might be hungry, but you shouldn’t be lethargic or vomiting.”
Eat healthfully. Even if you’re eating less food, you should still stick to a healthy diet that consists of whole, unprocessed foods, including nonstarchy vegetables, protein, and healthy fats, as well as a multivitamin, if recommended by your care team, and plenty of water to prevent dehydration and headaches. A healthy diet will help you lose or manage your weight and keep your blood sugar steady.
Keep your expectations in check. Intermittent fasting doesn’t work for everybody, and your medical team may not feel that it’s a good fit for you. It’s important to consult professionals before giving intermittent fasting a try, as going for long periods without eating when you have diabetes can be dangerous — or, at the very least, not give you the results you want.
Get support. If you do get the all clear to try intermittent fasting, consider following the plan with a friend or joining an online community or social support network for extra motivation to stick with it.
Additional reporting by Brian P. Dunleavy.
EDITORIAL SOURCES
Everyday Health follows strict sourcing guidelines to ensure the accuracy of its content, outlined in our editorial policy. We use only trustworthy sources, including peer-reviewed studies, board-certified medical experts, patients with lived experience, and information from top institutions.
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Lynn Grieger, RDN, CDCES
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Lynn Grieger is a registered dietitian-nutritionist, certified diabetes care and education specialist, certified personal trainer, and certified health and wellness coach. She comp...
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