Rationale and protocol for a randomized parallel intervention trial of two intermittent fasting approaches in patients with type 2 diabetes.

BACKGROUND

Type 2 diabetes (T2D) is a progressive disease driven by insulin resistance and β-cell dysfunction, often exacerbated by excess body weight. Intermittent fasting (IF) approaches, including intermittent energy restriction (IER) and time-restricted eating (TRE), have shown promise for improving glycemic control and facilitating diabetes remission. However, the feasibility and effectiveness of these IF approaches in individuals with T2D remain underexplored.

OBJECTIVE

This study aims to compare the feasibility, acceptability, and metabolic effects of IER and TRE in a randomized parallel trial in adults with T2D.

METHODS

Adults with T2D (N = 56) and overweight/obesity will be randomized to one of two interventions: IER (550-800 kcal/day on 2-3 days/week) or TRE (caloric intake within an 8-h daily window). Both groups will receive a comprehensive, remotely delivered diabetes education and behavioral support program over 6 months, followed by a 6-month low-contact follow-up during which participants continued the intervention on their own. Primary outcomes include feasibility (recruitment, retention, adherence) and acceptability. Secondary outcomes include changes in HbA1c, insulin sensitivity, insulin response to a mixed-meal tolerance test, body composition, and diabetes remission. Continuous glucose monitoring, metabolic and behavioral phenotyping will inform predictors of response.

CONCLUSION

This study is the first parallel trial to compare IER and TRE in patients with T2D and overweight/obesity. Results will provide critical data on the metabolic and behavioral responses to each IF approach, informing future strategies to personalize nutrition therapy in T2D.