Fasting with diabetes type 2 has been around for quite a while, but at the same time it remains something you might not want to try.
When people first hear of fasting, they normally think of it as a means to lose weight or cure a disease or illness. Nowadays, with the many medical advances that have been made, the idea of fasting has slowly changed. More and more people are now fasting to cure different diseases and illnesses, including diabetes type 2.
Can You Fast If You Have Diabetes?
There’s a lot of buzz about fasting — that is, not eating for a period of time or cutting back drastically — for better health. If you have diabetes, is it safe and will it help you lose weight, control your blood sugar, and maybe even need less medicine?
Perhaps. Some studies suggest fasting may be helpful for people with diabetes. But it’s not a mainstream treatment. The American Diabetes Association doesn’t recommend fasting as a technique for diabetes management. The association says lifestyle changes, including medical nutrition therapy and more physical activity, as the cornerstones for weight loss and good diabetes control.
If you’re thinking of trying a fast and you have diabetes, you’ll want to know what the risks are, how to avoid them, and why you should check with your doctor first.
Some fasts don’t allow any food at all. But on intermittent plans, you follow a pattern of fasting and then eat normally.
Some types of intermittent fasting plans include:
Alternate day fasting. You eat your regular diet one day, and then eat fewer than 600 calories the next day, repeating this pattern throughout the week. The popular 5:2 plan is related, in which you eat a regular healthy diet 5 days a week and cut down to about 500 to 800 calories on the other 2 days.
Time-restricted eating. This is when you get all your calories for the day during a specific number of hours. For instance, on an 8-hour plan, you might eat from 10 a.m. to 6 p.m. and then not again until the next day at 10 a.m.
Some people fast for several days or even weeks at a time — for example, for religious reasons. But not eating for more than 24 hours when you have diabetes can be dangerous.
More research is needed to know if it is safe long-term. Most studies of the effects of intermittent fasting have been done on overweight, middle-aged adults. More research is needed to determine if it is safe for people who are older or younger or people at a healthy weight.
Fasting may have some general health benefits. For example, it could cut down on inflammation, help with weight loss, and lower cholesterol. Fasting may also improve the way your body manages glucose (blood s
The American Diabetes Association notes that if you’re overweight or obese, weight loss can help lower your A1c level (a gauge of your blood sugar control over the last 2-3 months) and lower your risk for heart disease. Fasting isn’t required for weight loss.
Fasting may also affect how much insulin medication you need. In one study, people with type 1 diabetes who stuck with a fasting plan were able to lower their insulin dose.
Some organs that play a role in diabetes may benefit from fasting, too. Your body stores extra glucose in a form called glycogen in your liver. It takes your body about 12 hours to use that glycogen. If you don’t eat, your body begins to burn fat instead of glycogen for energy. That helps with weight loss. It also gives your liver and pancreas (which makes insulin, the hormone that controls blood sugar) a break.
When you fast, you’ll probably be hungry (at least at first). You might also feel drowsy and irritable. Not eating may give you a headache. And if you fast for more than a day or so, your body may not get enough of the nutrients it needs without supplements.
But the biggest danger of fasting if you have diabetes is that your blood sugar levels could go dangerously low (this is called hypoglycemia). That’s especially true if you take medication like insulin to control your diabetes. If you don’t eat, your blood sugar levels are lower and medication may drop them even more, which can lead to hypoglycemia. Hypoglycemia can cause you to feel shaky, pass out, or even go into a coma.
When you “break” your fast by eating, you may also be more likely to develop too-high blood sugar levels. Doctors call this hyperglycemia. This only happens if you eat too many carbohydrates. If fasting prompts you to overeat carbohydrate-rich foods, it may not be the right plan for you.
Before You Try Fasting
Talk to your doctor first. If you have type 1 diabetes, other health problems due to diabetes, or have had hypoglycemia, your doctor may recommend you not fast.
If your doctor says it’s OK to try, ask if you need to check your blood sugar more often or adjust your diabetes medication during and after fasting.
Watch for signs of low blood sugar. If you start to feel shaky, sweaty, or confused, your blood sugar may be too low. Stop fasting right away and do what you normally would to treat hypoglycemia. For example, eat a glucose gel or have a sugary drink followed by a small, balanced meal when your blood sugar level is back to normal.
Be careful about what you eat after fasting. Eating too many carbohydrates after fasting can cause your blood sugar levels to become too high. Choose healthy, balanced meals and snacks.
Use caution. Don’t do tough workouts while you’re fasting. Hard exercise can make your blood sugar levels dip, which can lead to hypoglycemia. Ask your doctor what activities are OK to do, or just take a break.
Stay hydrated. Having diabetes puts you at risk of dehydration, which can make your blood sugar harder to manage. Drink lots of water and calorie-free beverages when you fast.
Intermittent Fasting and Type 2 Diabetes: Is It Safe?
- Intermittent fasting may help with weight loss, which can reduce the risk of diabetes complications.
- While intermittent fasting can be done safely, people with diabetes may be at risk of hypoglycemia and hyperglycemia, due to fluctuations in blood sugar during and after periods of not eating.
- More research is needed to determine the long-term risks and benefits of intermittent fasting for people with diabetes.
Intermittent fasting is a type of diet that involves limiting your meals to a certain window of time, followed by a fixed period of eating little or nothing. The fasting period can last anywhere from a few hours to multiple days.
Some research has shown that intermittent fasting may provide benefits for people with diabetes, such as weight loss. However, major adjustments in eating patterns could lead to swings in blood sugar levels, which can be dangerous.
So, is intermittent fasting safe for people with diabetes?
Read on to learn more about the potential benefits and risks of intermittent fasting with type 2 diabetes.
Is intermittent fasting safe for diabetes?
Intermittent fasting may present some risks for people with diabetes.
If you use insulin or medications and suddenly eat much less than normal, blood sugar can drop too low. This is called hypoglycemia.
According to the American Diabetes Association (ADA), hypoglycemia can lead to symptoms such as:
- rapid heartbeat
- feeling nervous
- low energy
- blurred vision
Another potential danger of intermittent fasting with diabetes is high blood sugar. This is known as hyperglycemia.
Hyperglycemia can happen if you eat more than you typically do, which may be likely to occur if you’re especially hungry after a period of fasting.
High blood sugar levels can increase your risk of diabetes complications, such as:
- nerve damage (neuropathy)
- eye conditions and blindness
- kidney disease
- heart disease
- high blood pressure
Before starting any diet or weight loss plan, consider meeting with a member of your diabetes care team, such as a physician or dietitian, to make sure it’s safe for you.
Can intermittent fasting cause diabetes?
Some early research on animals shows that intermittent fasting may impact the pancreas and insulin resistance, but more studies are needed to determine its impact on diabetes in humans.
A 2020 studyTrusted Source looked at what happened to rats when they fasted every other day for 12 weeks. It found that the rats had an increase in belly fat, damage to pancreas cells that release insulin, and signs of insulin resistance.
It’s important to note that the findings may be different if humans took part in the same experiment. More research is needed to determine whether intermittent fasting can increase the risk of diabetes in people.
Can intermittent fasting reverse diabetes?
It may be possible for intermittent fasting to put diabetes into remission for some people, perhaps due to weight loss.
A 2018 case reportTrusted Source evaluated three people with type 2 diabetes who used insulin and fasted at least three times a week. Within a month, they no longer needed to use insulin.
They also had improvements in their body mass index (BMI), waist circumference, and HbA1C levels. After several months, the participants each lost about 10 percent of their body weight.
The sample size of that report was too small to make conclusions about how intermittent fasting can affect the majority of people with diabetes.
However, a larger study in 2018 found that nearly half of people with type 2 diabetes who lost weight were able to stop using diabetes medication and achieve remission.
Since intermittent fasting can be a way to cut calories, it may help people with diabetes lose weight and increase their likelihood of remission.
Other weight loss strategies may also help reverse diabetes, however.
Everyone is different, so what’s best for you may differ from what works best for someone else. Consult with a healthcare professional or dietitian to determine which strategy may be right for you.
What is intermittent fasting?
Fasting is when you stop eating or drinking (or both) for a stretch of time. People may fast for a variety of reasons, such as:
- as a religious practice
- in preparation for a medical procedure
- an attempt to lose weight
- to improve health in some way
Intermittent fasting is an eating pattern that involves periods of eating little to no food, followed by regular meals. Unlike many other diets, it usually focuses on restricting the timing of when you eat and drink, rather than the foods on your plate.
Intermittent fasting is often used as a way to lose weight through calorie restriction. It may provide certain benefits for people with diabetes, but there are risks involved.
Types of intermittent fasting diets for diabetes
While intermittent fasting diets come in a variety of styles, no particular one has been proven best for people with diabetes.
Here are a few common intermittent fasting diets:
- 16:8 intermittent fasting. People following this diet eat all meals within an 8-hour window, followed by 16 hours of fasting. Many people fast from 8 p.m. until noon the next day, and keep their eating window between noon and 8 p.m.
- 5:2 intermittent fasting. This is when you eat regular meals for 5 days, then have 2 days of fasting, during which you eat fewer than 500 calories per day.
- Alternate-day fasting. This is a full 24 hours without eating anything or only eating a small amount, followed by 24 hours of eating as usual.
- Early time-restricted feeding (eTRF). This restricts your mealtimes to the morning and early afternoon, followed by a fast that lasts the rest of the day and night.
What are the benefits of intermittent fasting for diabetes?
When done safely, intermittent fasting may provide some benefits for people with diabetes. If the eating plan leads to weight loss, people may be able to reduce the amount of diabetes medication they take.
Some people have been able to stop using insulin after fasting intermittently for a month or so, according to the small study on three people mentioned earlier.
More research is needed to determine if intermittent fasting can help most people with diabetes stop using insulin.
Other potential benefits include:
- improved insulin sensitivity
- lower blood pressure
- lower oxidative stress
- reduced appetite
- increased fat oxidation
More research is needed to determine the long-term benefits of intermittent fasting on glucose control and diabetes complications, according to the ADA.
Tips for intermittent fasting when you have diabetes
If you have diabetes and are thinking of trying intermittent fasting, here are some tips:
- Talk with your healthcare provider about adjusting medication or insulin dosages. You may need to change your diabetes treatment when trying a diet that could affect your blood sugar levels.
- Monitor your blood sugar levels. Long periods without eating can cause blood sugar to go too low, so check you glucose levels often.
- Check in on your mood. Many people find that restricting food intake can really affect their mood. Watch for signs like irritability, increased anxiety, and difficulty coping with stress.
- Monitor energy levels. Fasting can make you feel fatigued — something you might want to keep in mind if you’re driving or operating equipment.
- Balance your carbohydrates. Your body breaks down carbohydrates into glucose, which can lead to a spike in blood sugar. When you’re not fasting, try to balance starchy carbohydrates in your meals with vegetables and protein to avoid high blood sugar.
Diabetes and fasting: Can I fast during Ramadan?
Is it safe to fast during Ramadan if I have diabetes? Are there any other steps I should take to safely fast?
It’s safe sometimes. Some people may choose to not eat for a period of time (fast) for religious reasons, such as from dawn to sunset during the Islamic holy month of Ramadan.
However, talk with your doctor before you fast. He or she will likely explain potential risks of complications such as low or high blood sugar and dehydration. Your doctor may suggest that you avoid fasting if you’re at high risk of complications. If you choose to fast, your doctor and diabetes care team will likely provide you with education about managing your diabetes and adjusting your medications or insulin doses.
You may have a high risk of complications if you fast during Ramadan and you have one or more of the following:
- Type 1 diabetes
- Type 2 diabetes with poor blood sugar control
- Recent history of severe low blood sugar or diabetic ketoacidosis
- History of recurring low blood sugar or unawareness of low blood sugar
- Conditions such as severe kidney disease or blood vessel complications
- Diabetes and are pregnant
But it may be safe for you to fast with diabetes during Ramadan if you:
- Have type 2 diabetes that’s well-controlled
- Manage diabetes with medications or lifestyle therapy
If you choose to fast during Ramadan, your doctor and diabetes care team will likely recommend that you:
- Closely monitor your blood sugar
- Adjust your medication doses
- Watch for signs of low blood sugar
- Follow your doctor’s suggestions about food, drink and exercise
- Be ready to stop fasting if you have low or high blood sugar
You may be able to fast safely during Ramadan if you understand the risks, manage your diabetes and carefully follow your doctor’s recommendations.