Fasting and Diabetes: Understanding the Latest Guidelines

Fasting has been an integral part of religious practices for thousands of years. Considering the renewed interest in fasting for weight loss and other health benefits, patients with diabetes may be curious about fasting to enhance their health or maintain their cultural traditions.

Despite potential benefits, fasting with diabetes comes with a heightened risk for certain complications, particularly when patients undergo longer-term fasts, take multiple medications, or have additional health concerns.1 Striking the balance between respect for your patients’ belief systems and keeping them safe can thus be challenging.

To navigate this tenuous topic, we spoke with Nuha El Sayed, MD, MMSc. Dr Sayed is the Senior Vice President of Health Care Improvement. She worked closely on updating the American Diabetes Association’s Standards of Care in diabetes.

Dr Sayed explains that fasting is possible for some people with diabetes. Nonetheless, she still prefers to take a cautious approach. “I have scores of people with diabetes who are considered low risk for fasting who fast successfully…I also have many people who may be at higher risk for fasting who insist on fasting for religious or other reasons, but we agree on safety parameters to break their fast.”

Here’s what you should know about applying the latest guidelines and best practices to your patients.

Reasons to Support Fasting

Diabetes practitioners may be hesitant to condone fasting methods that interrupt a patient’s current diabetes care plan. However, some patients stand to benefit from fasting, and it shouldn’t be discounted before weighing the pros and cons.2

Since weight loss is a goal for many diabetes patients, finding effective strategies that patients are willing and able to try can be an essential aspect of diabetes management. Intermittent fasting is a weight loss strategy that includes structured fasting and “feasting” periods. There are a few different popular protocols for intermittent fasting, such as:

• Alternate day fasting: Restricting total calories to 500 or 600 per day every other day;
• The “5:2 Diet”: Limiting to 500 or 600 calories on 2 days per week, with normal intake otherwise; and,
• Time-restricted eating: Consuming calories during a set number of hours per day (such as 8 hours of eating and 16 hours of fasting).

Study findings show that intermittent fasting is a simplistic and practical approach that promotes similar weight loss results as seen with traditional calorie restriction (3-8% from starting weight). Intermittent fasting is also generally considered safe for those with type 1 and type 2 diabetes. However, patients on insulin or secretagogues may require medical monitoring during the fasting window.1

Furthermore, a growing body of evidence supports intermittent fasting for a wide range of health benefits related to heart health, inflammation, and immune regulation.3

Fasting can also offer mental and emotional health benefits. Findings from studies on religious fasting have shown a greater sense of community, self-acceptance, and reductions in feelings of anxiety and depression during the fasting period.2 Some patients may feel fasting facilitates a deeper connection between their body and mind by emphasizing their awareness and focus on eating mindfully and breaking away from unhealthy food habits.

Treating Patients Who Want to Fast

Because fasting for religious or other reasons is not uncommon, Dr Sayed says that it’s vital for health care professionals, including Registered Dietitian Nutritionists, certified Diabetes Care and Education Specialists, and others, to inquire about fasting practices among people with diabetes.

Dr Sayed advises providers to be mindful of the increased risk for hypoglycemia, dehydration, hyperglycemia, and ketoacidosis among people with diabetes who fast. She feels that there’s a need to provide education and support to accommodate individuals’ choices about religious fasting, including advice on glucose monitoring, medication and fluid adjustments, timing and intensity of physical activity, and meal choices pre- and post-fast.

Fortunately, some specific recommendations are already available for certain fasting periods, including Yom Kippur and Ramadan.2,4 These guidelines suggest ways to modify blood glucose monitoring and antidiabetic medications.

For example, studies on Ramadan suggest that glucose-dependent diabetes drugs — metformin, acarbose, thiazolidinediones, glucagon-like peptide-1 receptor agonists (GLP-1 RAs), and dipeptidyl peptidase-4 (DPP-4) inhibitors — aren’t as likely to cause hypoglycemia during fasting. As a result, there’s usually less need for adjustment while fasting.

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With prolonged fasting, my initial step is to understand the motivation behind a person with diabetes wanting to undertake such an approach. Given that usually safer alternatives [for weight loss] are available, I collaborate with the individual to develop a more medically safe alternative to meet their objectives.

Normal dosing of short-acting insulin secretagogues is also considered safe when administered during mealtimes. However, modern sulfonylureas may increase the risk for hypoglycemia. In addition, there are some concerns about dehydration with sodium-glucose cotransporter-2 (SGLT2) inhibitors, particularly since no water intake is permitted from sunrise to sundown during Ramadan fasts.2

Ideally, continuous or at least more frequent blood glucose monitoring during fasts can help increase patient awareness and self-efficacy. Patients should be advised that checking blood sugar does not constitute a break in the fast.

Identifying High-Risk Patients

No two diabetes patients are exactly alike; some can fast more safely than others. Most religions allow fasting exceptions for those who are unwell or not fit for fasting, but devout followers may be reluctant to excuse themselves from the practice.2 For instance, although pregnancy is a contraindication for fasting, this recommendation may be ignored when there is religious or community pressure to fast regardless.

Patients older than 65 years of age have a greater likelihood of comorbidities that may complicate fasting, including cardiovascular disease, impaired kidney function, and dementia. They may also take multiple medications that affect their glucose control.2 Additionally, in some cases, the fasting periods also affect sleep, physical activity, and other habits that influence metabolism.2 Rating systems to help determine if a patient is at risk or safe to fast can be helpful and provide an objective way to explain the reasoning behind your recommendations.2

How to Discuss Fasting With Patients

Dr Sayed recommends the following culturally sensitive steps when counseling diabetes patients on fasting:

• Understand the duration, frequency, and type of fast specific to each religion and how these factors might impact the individual’s diabetes management;
• Assess the type of diabetes, the patient’s type of therapy, and the presence and severity of any diabetes-related complications to tailor the advice and support;
• Provide clear guidance on how to adjust medications and fluid intake, monitor blood glucose levels, and recognize the signs of hypoglycemia, dehydration, hyperglycemia, and ketoacidosis; and,
• Discuss appropriate meal planning for pre- and post-fast periods to ensure that nutritional needs are met and blood glucose levels are stabilized.

Dr Sayed takes a similar approach with all patients, whether they do short-term fasting for religious reasons or weight loss. However, she says longer fasts warrant a deeper discussion.

“With prolonged fasting, my initial step is to understand the motivation behind a person with diabetes wanting to undertake such an approach,” she shares. “Given that usually safer alternatives [for weight loss] are available, I collaborate with the individual to develop a more medically safe alternative to meet their objectives.”

She goes on to explain, “Considering the potential risks, I generally advise against prolonged fasting for most people with diabetes. If a person insists on a prolonged fast against medical advice, strict and close medical supervision is recommended.”

Ultimately, patient care is a collaborative effort built on trust and respect. While providers often have legitimate concerns about their patients’ lifestyle choices, teamwork is always more effective. Take the time to understand your patients’ motivating factors before expressing concern or giving directives. Establishing a strong foundation paves the way to reaching common ground.

This article originally appeared on Endocrinology Advisor