Intermittent fasting improves weight loss in adults with type 2 diabetes, prediabetes

Key takeaways:

• Intermittent fasting resulted in weight loss across six studies, with a significant decrease in four.
• However, more research is needed to examine its long-term impacts.

BOSTON — Intermittent fasting was associated with weight loss and improved markers of glycemic control and anthropometric measures in adults with type 2 diabetes or prediabetes and overweight or obesity, data presented at NUTRITION showed.

“There are benefits when doing time-restricted feeding for those with prediabetes and type 2 diabetes,” AnnaMarie Couce, MS, RD, CLC, a pediatric dietitian at University Hospital in New Jersey, told Healio. “We found that it can improve weight, waist circumference, A1c and insulin resistance.”

For the study, Couce and colleagues searched online databases for terms like “diabetes mellitus,” “prediabetes” and “time-restricted feeding” to compile studies that explored how intermittent fasting (IF) in the form of time-restricted feeding (TRF) affects patients with prediabetes or type 2 diabetes and overweight or obesity.

Among the six studies evaluated, two included adults with prediabetes and four consisted of adults with type 2 diabetes. All used IF with an eating window of 6 to 10 hours over a course of 2 to 12 weeks.

Couce and colleagues found that IF was associated with weight loss across all the included studies, with a significant decrease in four out of the six studies.

Three studies also demonstrated a decrease in waist circumference, with a significant reduction present in two.

In addition, biochemical markers of glycemic control improved in five studies, fasting glucose levels significantly improved in four studies, and HbA1c improved in one study.

Further, two of the four studies that measured insulin sensitivity or resistance revealed significant improvements with IF.

Although one study found no benefits associated with TRF, Couce and colleagues noted that the finding was likely due to poor adherence and a weaker design.

Although IF showed several positive impacts, “the only problem is that it’s short term,” Couce said.

“We really need more studies to see the long-term effects,” she said. “We know that at least for a few weeks there are benefits, but what happens when you follow this for months or years? Is there really a drastic benefit to it? That’s what we really want to know.”

She pointed to oral hypoglycemic agents as another focus for future research.

“In this population, they weren’t on any insulin or any medications, so it would be interesting,” she said. “Do the results still stand with those who are taking insulin? Because that’s a big part of people with diabetes and prediabetes.”

Couce said that for physicians, “sometimes intermittent fasting is looked at as just a fad — there can be benefits in the short term.”

“Maybe if it’s not realistic to their lifestyle, we don’t want to promote it,” she said. “If it is making them have restrictive behaviors, that can affect your mental health.”

Ultimately, “it might not benefit every patient, but for some, there truly are some benefits to doing a fad diet,” Couce said.