Intermittent fasting has gained popularity among individuals who want to lose weight.

While this approach has shown promising results, it may not be the best eating plan for everyone.

When discussing weight loss options with your patients, some may show interest in intermittent fasting. It’s important to note that individuals with type 2 diabetes should only proceed with a full understanding of how certain eating restrictions could impact their health.

Here are some ways to discuss intermittent fasting, along with precautions associated with this eating plan for patients with type 2 diabetes.

How Does Intermittent Fasting Work?

Intermittent fasting is time-restricted eating. The particulars can vary from alternate day fasting to twice per week of limited eating (along with 5 days of unrestricted caloric intake) to time-restricted eating of 6-10 hours per day, said Vinni Makin, MD, an associate professor of medicine at Cleveland Clinic Lerner College of Medicine of Case Western Reserve University in Cleveland, Ohio.

“The thought is that this type of eating helps ‘flip’ the metabolic switch — move the body away from utilization of glucose from glycogenolysis as a source of energy to fatty acids and fatty acid-derived ketones,” said Makin, whose specialties include endocrinology, diabetes, and metabolism. “This, in turn, helps move from lipid synthesis and fat storage to mobilization of fat in the form of free fatty acids and fatty acid-derived ketones and also helps preserve muscle.”

Should Patients With Type 2 Diabetes Try Intermittent Fasting?

If a patient with type 2 diabetes asks whether intermittent fasting is a good idea, offering clinical information can be helpful.

“I would not advise intermittent fasting for a type 2 diabetic patient,” said Jesus Lizarzaburu, MD, a family medicine physician with TPMG Grafton Family Medicine in Yorktown, Virginia. “A type 2 diabetic patient already has developed habits that lead to diabetes. They already have difficult time restricting calories on a regular basis and starting something such as intermittent fasting would be a lot more challenging and difficult to maintain.”

However, if a patient talks to their doctor to ensure that proper guidelines are in place, intermittent fasting could prove to be beneficial even for those with type 2 diabetes, Makin said.

“Intermittent fasting would be a great option for a patient with diabetes who is motivated, checks blood sugars regularly, and knows how to adjust medications as insulin resistance improves along with blood sugar control during the dietary plan,” said Makin.

Doctors should emphasize that nutritious meals are especially important, as well as consuming adequate amounts of food during the eating window. “Unfortunately, the majority of our patients with diabetes are struggling with either access to nutritious food or the lack of dedicated time to plan meals ahead, making it difficult to be consistent with a diet regimen like intermittent fasting,” Makin said.

What Are Potential Nutritional or Metabolic Concerns?

One of the most important issues to consider in patients with type 2 diabetes doing intermittent fasting is the potential for hypoglycemia. This is particularly true for patients who are on antidiabetic medications that are associated with this condition, specifically insulin (both bolus and basal) and sulfonylureas, according to Makin.

It is important to adjust these medications prior to the patient starting an intermittent fasting regimen and then monitor them closely, Makin said.

“Sugars can fluctuate depending on compliance, and the patient might need to be given alternate medication plans if the sugars rise because of deviation from dietary protocol,” she explained.

In addition, inadequate protein intake is a concern with intermittent fasting and needs to be monitored carefully.

“Intermittent fasting — when combined with appetite suppressive diabetes medications like GLP-1 [glucagon-like peptide 1] receptor agonists — can also increase the risk of vitamin and mineral malnutrition and necessitate taking vitamin and mineral supplements,” Makin said.

It’s also beneficial to discuss staying hydrated with your patients. Even though intermittent fasting does not restrict water, dehydration is a concern for patients with diabetes. It might be a good idea to adjust these patients’ doses of medications like diuretics, sodium-glucose transport protein 2 inhibitors, or antihypertensives, she said.

How Can Medical Practitioners Help Patients Manage Weight?

Family doctors are commonly the first and most frequent contact for patients regarding healthy living concerns. This relationship can used to the patient’s advantage.

As a primary care doctor, you can introduce suggestions like how to eat better, increase physical activity, keep alcohol use in check, and improve sleep quality.

Some tweaking of meal routines could be an alternative to discuss, Lizarzaburu said. “I want my patients to have small successes frequently by doing things like no snacking between meals or not eating 4 hours before bed,” he said.

Being mindful of serving sizes is another valuable suggestion. “After that, be aware of how often and how much a person snacks, as those calories add up,” said Lizarzaburu. “Then, increase physical activities by walking, taking stairs, or doing some resistance exercise at home such as pushups, sit-ups, and/or squats.”

When Should Doctors Introduce GLP-1 Meds Into the Treatment Plan?

Lizarzaburu said most primary care doctors are trying to do the basics, which is encourage patients to eat an adequate number of calories per day; increase their intake of fruit, vegetables, and other healthy foods; and consume fewer of processed foods.

If patients still struggle to get on board with these eating habits, doctors usually turn to medications.

“GLP-1 medications come after long established medications for diabetes such as metformin,” Lizarzaburu said. “Although effective, GLP-1 medications are very expensive ($400-$1200) per month, long-term studies of what happens after discontinuation are not available yet. I fear that for many diabetics, any weight loss would go back to the patient’s starting point.”