Type 2 Diabetes and Fasting: What to Know

Most fad diets don’t live up to the hype, let alone serious scientific scrutiny. Intermittent fasting is an exception. These plans involve going without caloric foods or drinks for an extended period of time—anywhere from 16 hours to several days—and they have become increasingly popular. They are also effective in weight loss, according to research.

Type 2 diabetes patients are advised by doctors to lose weight. It can reduce the risk of developing the disease and improve blood glucose levels. Intermittent fasting is being studied by experts for Type 2 diabetes. There are also safety issues. “People with diabetes should be those who benefit most from intermittent fasting,” says Benjamin Horne, director of cardiovascular and genetic epidemiology at Intermountain Healthcare in Utah. “But these diets also present some of the greatest potential safety issues because of the medications that people with diabetes are typically taking.”

Horne co-authored several papers recently on the diabetes effects of intermittent fasting. One of these papers, published in the Journal of the American Medical AssociationIn 2020, we focused on the risks associated with these types of practices. “It’s so easy to start an intermittent fasting regimen on your own, so our main focus was on the safety issues surrounding fasting when you have a diabetes treatment plan already in place,” he says. Based on his and others’ work, Horne says that for most people with Type 2 diabetes—particularly those who are not taking medications to control their blood sugar—the research indicates that intermittent fasting is both safe and likely to be beneficial. However, intermittent fasting isn’t right for everyone. Horne along with experts discuss the potential risks associated with intermittent fasting as well as their benefits and most effective approaches.

There are risks to intermittent fasting

A.k.a. hypoglycemia is low blood sugar. Hypoglycemia (also known as low blood sugar) can lead to rapid heart beat, shaking, and other symptoms. If severe, it can induce weakness, seizures, or even death. People with Type 2 diabetes are at increased risk for hypoglycemia—especially if they go long periods without eating—and this was one of the first dangers experts looked at when assessing the safety of intermittent fasting. “If you are taking medications that are aimed at reducing the amount of glucose in your blood, together with fasting these can cause potentially fatal hypoglycemia,” Horne says. “It’s not a minor safety risk.”

The journal published a 2018 study. Diabetic MedicineNew Zealand researchers found that Type 2 diabetics who tried intermittent fasting had a higher incidence of hypoglycemia. This increase is consistent with other weight loss diets such as conventional ones that require people to eat fewer calories daily. All of the subjects in the study took drugs to decrease their blood glucose. “It was the medications, rather than the diet per se, that caused the hypoglycemia,” says study author Brian -Corley, a diabetes specialist at Capital & Coast District Health Board in New Zealand. Corley suggests that those who take these medications could lower their risk of dangerously low blood sugar levels by working with a doctor, closely monitoring blood sugar on fast days and learning how to deal with hypoglycemia episodes. In other words, intermittent fasting plans aren’t necessarily off the table for these patients; they just require a little more care. In the meantime, the study showed that intermittent fasting helped weight loss as well as improved measurements of fasting sugar and hemoglobin, A1C, overall quality of living, among other things.

For people who aren’t taking drugs to lower their blood sugar, Horne says the risk of hypoglycemia seems to be very low. “People should still consult with someone who treats diabetes—a physician such as an endocrinologist, or at least a nutritionist who is trained in diabetes treatment,” he says. He says that even those on blood sugar medications can attempt intermittent fasting if they work with an expert. “It’s not so much should they or shouldn’t they. It’s more the degree to which they should be monitored,” he says. Horne states that intermittent fasting for Type 1 diabetics is not recommended.

Dehydration is another major concern, along with hypoglycemia. People with Type 2 diabetes, such as those who have high blood glucose, are at greater risk of becoming dehydrated. People who fast intermittently may be at greater risk if they drink or eat less than usual. Food can actually provide as much or more than half of all the water people consume every day.

“With dehydration, people with diabetes can have a variety of negative outcomes,” Horne says. A person suffering from diabetes may be at risk for complications such as kidney damage, stroke or migraine headaches. “So if someone already has a problem with their kidneys—and oftentimes people with diabetes have some kind of kidney issue, if not full-blown kidney disease—dehydration can potentially cause harm,” he explains. While drinking water or other noncaloric liquids while fasting can reduce these risks, people who have Type 2 diabetes along with other chronic diseases—such as heart disease or kidney disease—probably shouldn’t attempt fasting diets. For older or frail patients with diabetes, the same applies. “Fasting puts stress on the body and organs,” he says. If you’re weak or unwell, going without food is probably a bad idea.

Intermittent fasting can pose additional health risks. But these concerns are not only relevant to Type 2 diabetics. For example, nutrient deficiencies, inadequate protein intake (especially if you’re older), and other forms of malnutrition are possible if you’re fasting. Also, the safety profile of intermittent fasting is not well mapped among women who are pregnant or breastfeeding, or in young kids—all groups with important nutritional requirements different from those of the general population. Experts recommend that experts not fast these individuals until better understanding of both the risks and benefits is available.

While hidden dangers could emerge, intermittent fasting—with expert oversight—seems to be safe for most people with Type 2 diabetes.

Continue reading: The Risks of Type 2 Diabetes for People with Health Problems

Intermittent fasting has many benefits

Although intermittent fasting is not without risks, some may find it more beneficial than other options. An analysis of 2017 data in The World Journal of DiabetesIntense fasting for just two weeks led to substantial weight loss of more than 3lbs (on average), and improved glucose levels. “It’s possible that intermittent fasting could lead to reduced insulin resistance,” says Kerry Mansell, co-author of that study and a professor in the College of Pharmacy and Nutrition at the University of Saskatchewan in Canada.

The hypothesis has been supported by scientific research. Research on diabetes patients has shown that intermittent fasting can increase insulin sensitivity as well as reduce blood insulin levels. This is an important finding. “Essentially, fasting is doing what we prescribe diabetes medications to do, which is to improve insulin sensitivity,” Horne says. A small study of three patients found that intermittent fasting allowed them to quit taking insulin. That study’s findings still need to be replicated in a larger group. These results, however, are positive. High levels of inflammation are associated with insulin resistance, which is also linked to increased risk factors for developing cardiovascular disease. “Even when people aren’t losing weight on a fasting regimen, some research has found that insulin sensitivity improves markedly,” Horne says. “This is something you typically don’t see with other caloric-restriction diets.”

These are the benefits of fasting. Many theories are possible, but not all of them could be correct. One of the leading hypotheses—which is already supported by solid research—is that fasting kicks off a kind of cellular cleansing process that removes old or unhealthy cells and allows new ones to flourish. Based on this work, some experts argue that the human body isn’t designed for the modern food environment and its three-meals-a-day-plus-snacks eating schedule. They say intermittent fasting may more closely resemble the way humans ate for most of our species’ history.

This is a complex issue that requires more research. Research has indicated that people suffering from Type 2 diabetes may benefit from intermittent fasting.

What is the best fasting strategy?

The term intermittent fastingThis does not necessarily refer to one practice. Many different methods can be included in intermittent fasting. Three of the most well-studied and popular options are time-restricted, alternate-day fasting and 5:2.

The first of these—time-restricted eating—involves squeezing all of your day’s calories into a single “feeding window” of six to eight hours. This means that someone following this diet might eat from noon to 6 p.m. every day and avoid eating caloric foods or drinks the rest of the day. Meanwhile, someone on an alternate-day-fasting diet eats normally one day, but the next day consumes few or no calories. The 5:2 diet is a way to eat normally on five days per week and fast the second two.

You can find many options for each plan. At this point, it’s unclear which of these, if any, is optimal for people with Type 2 diabetes. “I think time-restricted eating is probably the most common, followed by fasting two days a week,” Horne says. “But at the moment, I would say there is not one plan that stands out as a best option.” The “right” plan, he adds, is the one a patient will stick with. Even if the more intense fasting programs turn out to be most beneficial, that doesn’t really matter if people can’t adhere to it.

Continue reading: A link between Type 2 Diabetes and Psychiatric Disorders

How do you start an intermittent fast?

Always talk with your physician. They should be able to help you weigh the benefits and risks, identify dietary approaches to avoid nutritional deficiencies, and, if necessary, adjust any medications you’re taking to avoid problems. “Safety must come first,” Horne says.

However, don’t be surprised if your health care provider isn’t enthusiastic about fasting diets. These plans are still relatively new, and they’re generally not taught in medical school. “People may encounter pushback, or their physician may not be very familiar with these regimens,” Horne says. If your doctor says that fasting isn’t right for you, that’s one thing. If your doctor seems to be dismissive about fasting, you might want to seek a second opinion from someone who is familiar with such plans.

Some people may find intermittent fasting risky. However, there are now signs that intermittent fasting could be an effective or superior alternative to the traditional weight-loss programs for Type 2 diabetes sufferers.

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