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Stephanie Turner, NP

Medically reviewed by:
Stephanie Turner, NP

An intermittent fasting eating plan restricts food intake during certain hours.

Aug. 4, 2025

More than 11% of Americans are currently living with diabetes.1 Diabetes can cause high blood glucose levels. Without treatment, diabetes can cause organ damage, vision loss, and nerve pain. Some patients experience life-threatening complications.

Fortunately, diabetes is often manageable, and many people with diabetes live long, healthy lives. However, getting treatment and managing your blood glucose levels is critical. You may have heard that an intermittent fasting (IF) eating plan can help you lose weight, manage your blood sugar, and get your diabetes under better control.

But how does IF work, and is it safe for people with diabetes? Let’s look at the facts.

What is intermittent fasting (IF)?

An intermittent fasting eating plan restricts food intake during certain hours. IF doesn’t necessarily restrict calorie intake overall, and contrary to popular belief, it doesn’t always result in weight loss.

IF aims to adjust a person’s metabolism by causing the body to fast for a certain period each day or certain days of the week. Following an IF eating plan may help your body burn more fat or use up stored glucose. It might also change how your cells respond to insulin.2

How intermittent fasting works

Fasting schedules can vary, and different types of intermittent fasting diets are effective in patients with diabetes.2,3

In a time-restricted IF eating plan, a person might eat only for eight hours each day. For example, the person might consume all their meals between 12 pm and 8 pm. During the remaining hours, the person must fast.

Another popular eating plan is known as alternate-day fasting. With this method, a person may fast during one day and then eat normally the next. A person might also create a weekly calendar where they fast two days out of each week and eat normally during the remaining five.3

Fasting rules can vary. A fasting person often consumes only noncaloric beverages like water and unsweetened tea and coffee. People practicing IF can adjust their eating plan to suit their work schedules and personal routines. Some may choose to practice day-long fasts on weekends. Others may choose a time-restricted schedule and sleep through most of their fast period.

If you decide to explore IF, you can work with your doctor to choose a fasting method that works with your lifestyle.

How does IF affect the body?

When a person abstains from food for several hours, the body may begin to access glycogen.3 Glycogen is a form of glucose that your body stores in your liver and muscles. As your body uses up available glycogen, it may burn stored fat for energy. This process could help to stimulate the metabolism and alter hormone levels.4

Some research suggests that IF can help patients manage their weight by reducing their calorie intake. Weight loss can make it easier for your body to manage your diabetes. Other research suggests fasting might help control blood pressure, lower cholesterol levels, and reduce inflammation.4 Managing blood pressure and cholesterol can improve your health and reduce your disease risk. Controlling inflammation might also reduce your chances of developing many diseases.

Some scientists even believe that reducing inflammation may help to slow the aging process and reduce a person’s risk of cancer or dementia.5 However, more research is needed to explore these possible health benefits. Studies examining the benefits of fasting for overall health are still limited.

Fasting and diabetes

A growing body of research suggests that fasting may help control diabetes by stabilizing their blood sugar levels. How does fasting affect diabetes? Let’s explore the process in more detail.

Benefits of intermittent fasting for diabetes

As your body processes food, it breaks down carbohydrates and produces glucose. Your body tries to manage its blood glucose levels by releasing insulin. This hormone tells the cells in your body to absorb glucose from your bloodstream, which lowers your blood glucose levels. If your body isn’t able to produce enough insulin, you may develop diabetes.3

Diabetes can also develop if you have insulin resistance.6 People with insulin resistance may produce enough insulin, but their bodies don’t respond well to this hormone. Insulin prompts their cells to absorb glucose, but they don’t receive the message. Their blood sugar continues to stay high.

The pancreas, the organ responsible for making insulin, tries to solve the problem by creating more insulin. For a while, this might work. However, the pancreas eventually cannot produce enough insulin, and diabetes can develop.

So, how does IF help manage your diabetes? To start, your body naturally uses glucose for energy.3 When you aren’t eating, insulin levels in your body begin to drop. Your body can then burn glycogen and fat. This process may result in weight loss and can help reduce cholesterol and insulin levels.

Studies performed on individuals with diabetes have shown that IF can help reduce A1C levels and better manage blood sugar.7 IF may help your body to become more sensitive to insulin, which reduces the amount of insulin your body needs to manage glucose. Over time, your health may improve, and your blood glucose levels may stabilize.

Risks of intermittent fasting for diabetes

IF can cause a variety of side effects, including:8

  • Dizziness
  • Fainting
  • Weakness
  • Nausea
  • Insomnia
  • Headaches
  • Excessive hunger

Some people find it easy to adopt an IF lifestyle, while others become uncomfortable when forced to fast for long periods. You may feel hungry while fasting, which can become distracting or frustrating.

Your blood sugar levels may drop too low, which may cause you to feel dizzy or weak. Fainting and falls sometimes occur when fasting. You may have a dangerous accident if you faint or become dizzy while driving a car or riding a bike. You might also become injured if you faint or fall inside your home.

Some people may become dehydrated while fasting. During fasting periods, participants are encouraged to drink plenty of water and black tea or coffee. However, some people may forget to keep up their fluid intake and may become weak or faint from dehydration.

A diabetes diagnosis can complicate matters further. If you have diabetes, IF might help you control your blood glucose and improve insulin sensitivity, but fasting may also cause some complications. You will need medical supervision if you choose to try IF.

Is intermittent fasting safe for people with diabetes?

IF isn’t right for everyone, and people with diabetes need to take added precautions when trying IF. Talk to your doctor before you change your diet or try fasting. Your doctor can help you create a safe eating plan and talk to you about the potential risks and side effects of fasting.

I have diabetes. What should I discuss with my doctor before doing intermittent fasting?

During your wellness appointment, your doctor can provide you with more information about your diabetes diagnosis. Some patients may have a form of diabetes that doesn’t respond well to fasting. If you have labile diabetes, also known as brittle diabetes, your symptoms may worsen if you try to fast.9 Your doctor may recommend that you avoid IF plans if you have this type of diabetes.

If you’re pregnant or breastfeeding, be sure to tell your doctor before trying to fast. Fasting may not be recommended in your case, since a low-calorie diet might affect your health, your baby’s development, or your ability to breastfeed. However, doctor-supervised fasting may be safe for some patients.10 Talk to your pregnancy care provider to learn more about possible risks and benefits for you and your baby.

IF may not be recommended for older adults, especially those over 70.11 It can be especially dangerous for older adults who have a history of falls, cognitive problems, or head injuries. These individuals are at a higher risk of dehydration or disorientation while fasting. Older adults are also more likely to develop serious injuries if they become faint and fall.

Some prescription medications also contribute to dehydration or feelings of faintness. Before considering IF, review all your prescription medications with your doctor. Be sure to tell your doctor about any medicines you have been prescribed by a different health care provider. Tell your doctor about any over-the-counter drugs or supplements you’re taking, too.

Finally, make sure to let your doctor know if you have a history of mental illness or eating disorders (ED). Fasting can be very dangerous for people with ED, since it can trigger a relapse or encourage unhealthy eating practices.12 Be honest with your doctor about your experiences with ED and listen to the advice provided by your health care team.

Getting started with intermittent fasting

If your doctor agrees it’s safe for you to try IF, they can advise on safety precautions. Your doctor may ask you to check your blood sugar more frequently than usual and to break your fast if your blood sugar drops to a certain level. Be sure to follow your doctor’s directions. Breaking a fast is sometimes necessary to protect your safety.

Your doctor may also recommend avoiding certain foods, especially when breaking a fast. As a general rule, it’s best to avoid processed or sugary foods while fasting. Instead, consider a meal that contains whole grains, lean protein, and plenty of fruits and vegetables. Your doctor can provide more information about recommended foods.

Managing diabetes isn’t always easy, but WellMed is here to help. We have the resources you need to take charge of your health and get your blood sugar under control.

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