Fasting and diabetes: Risks and benefits of intermittent fasting

While the practice of fasting has been around for millennia, intermittent fasting has recently surged in popularity. The biggest benefit people look to get from this type of fasting is weight management, but it offers a ton of other advantages, too.

Here's what you need to know about intermittent fasting as well as considerations to take into account when combining fasting and diabetes.

What is intermittent fasting?

Intermittent fasting refers to an eating pattern in which people go for extended periods of time with little or no food intake on a regular (and recurring) basis. For example, if you were to try the common 16:8 intermittent fast, you would avoid food for 16 hours and then have an eight-hour period of time when you would eat normally. In effect, you would be shrinking your normal "window of eating time" down to eight hours a day, every day. There are numerous other intermittent fasting schedules that others have opted for:

The 5:2 plan. With this fasting schedule, you choose two nonconsecutive days per week and eat very few calories on those days. For the other five days of the week, you eat normally.
Eat, Stop, Eat. Just like it sounds, this type of fasting encourages people to eat one day, fast the next, and then eat on the third day. Afterward, they start all over again with a day of eating.
Alternate day fasting. When following this regimen, you eat every other day and completely fast (or eat very few calories) on the in-between days.

Benefits of intermittent fasting

A significant amount of research has been done in both humans and animals around intermittent fasting. While the connection between fasting and diabetes is still being examined, scientists have determined that intermittent fasting is associated with the following benefits, according to a study in Ageing Research Reviews:

Decreased insulin resistance (which means decreased insulin doses for people with diabetes).
Decreased LDL (the "bad" cholesterol).
Weight loss.
Decreased inflammation.
Changes in gene expression (the way your body uses DNA to make protein), which can potentially extend the length of your life.
Improved repair of damage to your body's cells.

Since the most common complication of diabetes is heart disease, decreased LDL, decreased inflammation, and improved cellular repair are benefits definitely worth noting. Each of these advantages has the potential to lessen a person's risk of heart disease.

Risks of intermittent fasting and diabetes

For all the benefits that intermittent fasting offers, there are also some risks to be aware of, especially if you live with diabetes. Here's what you should know:

The biggest risk of intermittent fasting with diabetes is hypoglycemia (severely low blood glucose levels). It can be especially tricky to manage a dose of long-acting insulin if you follow a plan like Eat, Stop, Eat — you'd need to continually think about which kind of day is coming up and how your long-acting insulin dose needs to be adjusted to accommodate that day. Of course, short-acting insulin doses would need to be adjusted too, but they're generally easier to manage with fasting because they're taken at mealtimes. So, no food, no short-acting insulin — unless you need to correct.
Deficiencies can occur if you don't consume enough nutrients over an extended period of time. Additionally, dehydration can occur if you avoid drinking water in addition to eating food as part of your fasting. This can lead to more serious complications in people with diabetes, so it's important you manage your intake thoughtfully.

What to do before you try intermittent fasting with diabetes

If you have diabetes and you want to try intermittent fasting, it's important to first consult your healthcare team. Your physician, registered dietitian, and certified diabetes care and education specialist can all serve as resources and help ensure you have a plan to keep your blood sugar in check. You'll need to monitor your blood sugar closely, and be prepared to treat any highs or lows that may occur — the more help you can have in this regard, the better!

If, after speaking with your team, you'd like to determine the benefits of fasting for yourself, don't let diabetes stand in your way. Choose a fasting plan that minimizes risk (such as the 16:8), make adjustments to your insulin schedule, and keep a close eye on your blood sugar levels.

To help make your experience with fasting and diabetes a little easier, you may want to consider tapping technologies like continuous glucose monitors (CGMs) and insulin pumps. Both of these devices allow you to automate aspects of your diabetes management, which can provide increased confidence and peace of mind.

Curious to learn more about which CGM would fit your life best? Check out this article on matching a CGM to your lifestyle to get a better idea of the available devices and special features.