Targeting when a person eats, not simply caloric intake, may affect diabetes and other health outcomes.

Time-restricted eating has been found to improve cardiometabolic health, insulin resistance, glycemic management, and blood pressure independent of weight loss, said Courtney M. Peterson, PhD, MSc, MA, MS, University of Alabama at Birmingham.

Dr. Peterson addressed the potential for time-restricted eating to inhibit the progression of prediabetes to type 2 diabetes in the Saturday, June 22, symposium Intermittent Fasting in Various Forms of Diabetes Care.

“Unfortunately, about one-quarter of individuals with prediabetes will develop type 2 diabetes in three to five years,” Dr. Peterson said.

However, there is evidence that shows prediabetes is reversible, she noted. Weight loss can help facilitate better glycemic management and lower A1C levels. And time-restricted eating has been shown to promote weight loss.

Lisa S. Chow, MD, MS, University of Minnesota, said historically, obesity has not been an issue in type 1 diabetes, but that is no longer the case. In the 1980s, only 3.4 percent of patients with type 1 diabetes were obese, compared to 28­­–37 percent in the 2020s.

Fasting may be avoided among these patients to prevent hypoglycemia and ketoacidosis, but Dr. Chow said patients with type 1 diabetes can safely fast—with some precautions—and experience the related weight-loss and glycemic-management benefits associated with this kind of restricted eating. Safe fasting can be done—and often is for religious reasons—with education on how to avoid hypoglycemia and a reduction of insulin requirements, she explained.

Dr. Chow also presented research showing that a person’s eating window correlates with their body mass index (BMI). The smaller the eating window, the lower the BMI.

People eat “all the time,” only stopping when they sleep, she said, citing research showing for about 50 percent of people across all races, there is a 15-hour window between the first food and the last food they consume in a day.

Dr. Peterson highlighted how intermittent fasting, specifically time-restricted eating, can have benefits that go beyond weight loss.

“What’s interesting is that with time-restricted eating, it’s more customizable than other diets,” Dr. Peterson said, explaining that time-restricted eating allows a person to set their eating window earlier or later in the day, and they can practice it with or without cutting calories. However, the effects of time-restricted eating could depend on the time of day one eats.

“If you average over the course of the day, we found that early time-restricted eating decreases mean 24-hour glucose levels,” Dr. Peterson said.

This could be due to a “second-meal effect,” which occurs when a person eats two meals before their insulin levels return to baseline and does not experience a glycemic excursion with the next meal.

Time-restricted eating also has the potential to affect reproductive health. Sofia Cienfuegos, PhD, MS, University of Illinois at Chicago, concluded the session with a discussion on the dynamics of time-restricted eating and polycystic ovary syndrome (PCOS), which is often associated with insulin resistance.

“The first line of therapy for PCOS is lifestyle changes: diet, exercise, and behavior modifications for weight management. Complex, not very straightforward,” she said. “However, when you think about the first line of therapy being lifestyle changes, it’s very complex to prescribe lifestyle changes. What’s that? What type of diet?”

With so many diets and exercises to choose from, it can be a challenge for clinicians to prescribe one specific lifestyle change, she added.

“I’m trying to find a strategy that can make lifestyle changes easier for both patients and clinicians,” Dr. Cienfuegos said.

Dr. Cienfuegos highlighted research demonstrating the benefits of time-restricted eating for managing PCOS symptoms, such as reducing systemic inflammation, improving insulin sensitivity, and decreasing androgen production.

The session can be viewed on-demand by registered meeting participants on the virtual meeting platform. If you haven’t registered for the 84th Scientific Sessions, register today to access the valuable meeting content through Aug. 26.