In Fasting Safely with Diabetes, first published in August 2020, Martin M. Grajower, MD, discussed strategies for helping patients with diabetes avoid health complications while fasting. As the COVID-19 pandemic has progressed, it has become well-established that having diabetes, especially type 2, is a risk factor for developing a more severe case of COVID-19. Here, Dr. Grajower shares strategies for fasting safely during the pandemic. This update should be read as a companion piece to the original article.

With the recent increase in transmissibility of the omicron variant, and with the risk of new variants developing from around the world, anyone with diabetes who wishes to fast, to honor the precepts of their religion or for dietary or other reasons, has a significant decision to make. A review of this subject—focused on fasting for Ramadan—was published in April 2020. It recommends classifying people with diabetes according to three risk categories.

HIGH risk: People with type 1 diabetes or type 2 diabetes, with an A1C >8.5%, and ANY of the following

• lack of awareness of hypoglycemia
• severe or recurrent hyperglycemia in the preceding three months
• history of diabetic ketoacidosis in the preceding three months
• acute illness (which would include COVID-19)
• pregnancy
• significant comorbidities, such as chronic kidney disease or heart failure

MODERATE risk: People with type 2 diabetes and ANY of the following

• A1C 7.5-8.5%
• taking basal insulin treated with a sulfonylurea, DPP-4 inhibitor, SGLT2 inhibitor, or GLP-1 receptor analog
• living in a household where someone has symptomatic COVID-19

LOW risk: People with type 2 diabetes and ALL of the following

• A1C <7.5%
• not taking medication to lower blood glucose or taking only metformin
• living in a community affected by COVID-19

According to the recommendations of the review authors, someone at high risk “must not fast.” Someone with moderate risk “should not fast.” And someone with low risk should take “adequate precautions if they choose to fast.”

Finally, the recommendations provide specific advice for people who fast during the month-long Ramadan that co-occurs with the COVID-19 pandemic. These precautions include checking blood sugar at least four times a day: prior to the meal in the morning (suhoor), two hours into the fast, just before breaking the fast at sunset (iftar), and two hours after breaking the fast.

The above guidelines were published by a consensus of several physicians. Personally, I would consider someone taking a DPP-4 inhibitor or GLP-1 receptor analog also a low risk in most cases, similar to metformin, due to the rare risk of developing hypoglycemia.

I would also add that people who fast for shorter periods, such as a 24-hour fast for Yom Kippur, or who intermittently fast during the COVID-19 pandemic should NOT fast during any acute illness, including COVID-19. For additional guidelines for managing these fasts, including adjusting medications, see

• Management of Diabetes Mellitus on Yom Kippur and Other Jewish Fast Days 
• 24-Hour Fasting with Diabetes: Guide to physicians advising patients on medication adjustments prior to religious observances (or outpatient surgical procedures)

Continuous glucose monitoring (CGM) might be a significant aid in safely managing someone at low or moderate risk, but who plans to fast for an extended period and is not likely to do frequent fingerstick glucose monitoring. Although the patient may have to pay out of pocket for the CGM, the expense might be justified for use during an extended fasting period, especially since the latest CGMs offer low and high glucose alarms.

These guidelines should be adjusted to meet the needs of a given patient. Health care professionals can encourage their patients to speak with them to decide whether to fast during the pandemic, and if yes, how to do so safely.

During the pandemic, how have you addressed the subject of fasting with your patients who have diabetes?