Category: Type 2 Diabetes

Intermittent Fasting in Patients with Type 2 Diabetes

Currently experiencing a surge in popularity, intermittent fasting has become an increasingly adopted dietary regimen due to its many purported health benefits. The concept of intermittent fasting refers to a spectrum of nutritional behaviors that aim to intentionally disrupt energy consumption for extended periods of time, for example, for between 16 and 24 hours on a regular intermittent schedule. In some intermittent regimens, individuals restrict food consumption to a 6- to 8-hour period, while in others they fast for a full 24 hours during several days of the week.

Some individuals may be inclined to adopt these dietary patterns as a means of weight loss or for their promised health benefits supported by anecdotal evidence, including the treatment of type 2 diabetes which remains unproven and untested entirely. While caloric restriction and weight loss are known to beneficially influence health outcomes in patients with type 2 diabetes – leading to improved glucose control, hypertension, and abnormal lipid levels – achieving them with intermittent fasting presents concerns.

Published on July 2, 2020 in JAMA, a new viewpoint underscores the limited body of evidence of the health benefits of intermittent fasting among type 2 diabetes patients and reveals the potential adverse complications that may result from this approach if patients are not carefully monitored.

Intermittent Fasting and T2D

To date, intermittent fasting in patients with T2D has only been studied in a few small, short-term trials yielding limited evidence of its benefit. Recently, a team of researchers examined the evidence for the health benefits and safety of intermittent fasting in this group of patients specifically. For the purposes of the study, intermittent fasting was defined as time-restricted feeding, or fasting on alternate days or during 1-4 days of the week, with only water, juice, or bone broth and no more than 700 calories consumed on fasting days.

In total, the study’s authors found seven published studies of fasting in T2D patients – only one trial had over 63 patients. Most studies were short in duration, occurring over 4 months or less, and evaluated five different fasting frequencies. All reported a connection between intermittent fasting and weight loss, while the majority also noted decreased A1c and improved glucose levels, quality of life, and blood pressure. Due to the lack of homogeneity in design, measures, and regimen styles, clinically meaningful conclusions could not be drawn.

In addition, only one study addressed the safety of two intermittent fasting regimens, finding that both increased the incidence of hypoglycemic events despite the use of a medication dose-change protocol.

Improved Glucose, Heightened Risks

The primary implication of the latest findings is that intermittent fasting may be less safe than caloric restriction, although it could be equivalently effective. Patients with existing diabetes who experienced weight loss saw a benefit of improved glucose, blood pressure, and lipid levels, according to the researchers.

While weight loss associated with intermittent fasting appears to be similar to that attained with caloric restriction, in the case of type 2 diabetes patients it can pose a risk of glycemic variability. Hypoglycemia can occur during fasting and hyperglycemia during feeding times, researchers note, and presents potentially dangerous clinical implications.

“Studies have raised concern that glycemic variability leads to both microvascular (eg, retinopathy) and macrovascular (eg, coronary disease) complications in patients with type 2 diabetes,” the authors cautioned. As such, the report highlights the need for continuous glucose monitoring aimed at detecting glycemic variability in susceptible patients as well as throughout studies of clinical interventions involving intermittent fasting in T2D patients.


Although further evidence is needed, the study’s lead author, Benjamin D. Horne, PhD, MStat, MPH, concluded that he would recommend intermittent fasting for patients with type 2 diabetes with caveats due to safety issues. These can include factors such as low blood pressure, weakness, headaches, dizziness – all of which are important considerations alongside the risk for hypoglycemia. Thus, caloric restriction may be a safer choice for certain patients.

Horne recommends giving patients intervention options to choose from as some may be better positioned to handle intermittent fasting. Until intermittent fasting is proven more effective at controlling diabetes, the currently available study data implicate that such regimens for patients with type 2 diabetes should be approached with caution, the risk of hypoglycemia closely monitored, and medications carefully adjusted to ensure both safety and efficacy of nutritional interventions.


Latest Statistics: 34 Million Americans Have Diabetes

Previous data indicates that diabetes is the leading risk factor for hospitalizations across the United States, with a total of 7.8 million hospital discharges reporting the condition as any of the listed diagnoses among adult patients aged 18 or older. Although incidence rates have slowed in recent years, approximately 34 million adults in the United States have type 1 or type 2 diabetes today. Of those, about 7.3 million meet laboratory criteria for diagnosed diabetes, however, are unaware or do not report having the disease. 

In a recent attempt to calculate the national estimated disease burden and prevalence of diabetes, the Centers for Disease Control and Prevention released the 2020 National Diabetes Statistics Report, which can be accessed in full here. Their findings indicate a decrease in the number of newly diagnosed diabetes cases in recent years among most – but not all – demographics and highlight the importance of more targeted prevention methods focused on adolescents specifically. 

Data for the report were derived from the National Health and Nutrition Examination Survey, the National Health Interview Survey, the Indian Health Service (IHS), National Data Warehouse, the Behavioral Risk Factor Surveillance System, the U.S. Diabetes Surveillance System, and the U.S. resident population estimates. Researchers established diagnosed diabetes status based on self-reported patient information; undiagnosed diabetes was determined by fasting plasma glucose measures or HbA1c levels.

Current Estimates

In 2018, new cases of diagnosed diabetes grew by 1.5 million, equivalent to about 6.9 diagnosed patients per 1,000 persons, similar to 2006 incidence rates. That year an estimated 88 million adults had prediabetes, although many of them may have been unaware of their condition.

Currently, adults aged. between 18 to 44 years experience lower diabetes rates than those aged between 45 and 65 as well as those aged above 65 years. However, younger demographics are increasingly at risk for developing the condition.

Incidence of New Cases in Youth

Per the latest statistics, the number of new diabetes cases decreased throughout the past decade in the United States with one exception – the overall incidence of type 1 diabetes significantly increased among children and adolescents between 2002 and 2015. The largest change was observed among children of Hispanic descent. In addition, the prevalence of type 2 diabetes also increased in this age demographic with changes consistent across all racial groups.

Prevalence and Risk Factors

Despite the decreased incidence of new cases in adults, the latest data from the Centers for Disease Control and Prevention reveal that the age-adjusted prevalence of total diabetes increased among adults between 1999 and 2016 – up from 9.5% in 1999-2002 to 12% in 2013-2016. These results held steady in 2018 at 6.7 per 1,000 adults compared with 2000 data, which reported a rate of 6.2 per 1,000 persons. 

Meanwhile, the age-adjusted results for 2017-2018 found the prevalence of diagnosed diabetes was highest among Native Americans and Alaskan Natives, Hispanic adults, and African Americans.

“Among adults, prevalence varied significantly by education level, which is an indicator of socioeconomic status,” the report explains. “Specifically, 13.3% of adults with less than a high school education had diagnosed diabetes vs. 9.7% of those with a high school education and 7.5% of those with more than a high school education.”

Common risk factors for diabetes-related complications showed that about 22% of diagnosed adults were tobacco users, 15% reported current smoking, and 36.4% had quit smoking. Furthermore, 89% of those with diagnosed diabetes were overweight or had obesity while 38% were physically inactive. 


As current literature proves, diabetes has a significant burden on population health and outcomes, contributing to increased risks of comorbid cardiometabolic conditions as well as adverse complications. The growing number of newly diagnosed cases in children and adolescents indicates an urgent need for age-specific prevention and management protocols as well as increased efforts to combat the disease in younger populations as early onset diabetes tends to predispose patients to poorer outcomes. 

The CDC’s latest report outlining trends in prevalence and estimates of diabetes burden can be accessed here.