NCT07056465

Exploring Adherence and Acceptability of an Intermittent Carbohydrate Restriction Regime in Free-Living Adults: A Feasibility Study

Acceptability of, and Compliance to a Novel Intermittent Carbohydrate Restriction Dietary Intervention

• Status: Completed
• Phase: N/A
• Study type: Interventional
• Enrollment: 37 (actual)
• Sponsor: University of Surrey · Academic / Other
• Sex: All
• Age: 18 Years – 60 Years
• Healthy volunteers: Accepted

Summary

This study investigates a novel dietary approach called Intermittent Carbohydrate Restriction (ICR), which involves reducing carbohydrate intake on selected days of the week while allowing habitual eating on other days. Previous research suggests that intermittent dietary strategies may improve metabolic health and support better adherence compared to continuous calorie restriction. In this single-arm feasibility study, 40 healthy adults will follow the ICR protocol for 4 weeks. Outcomes including body weight, body fat percentage, waist circumference, and resting metabolic rate will be measured before and after the intervention. Dietary adherence, changes in habitual intake, and participant experiences will be assessed through food diaries, 24-hour recalls, questionnaires, and exit interviews. The primary aim is to evaluate the acceptability and adherence to the ICR protocol in free-living conditions. Secondary aims include exploring its effects on body composition and diet-related behaviours, with the goal of informing future long-term dietary interventions.

Detailed description

Intermittent energy restriction (IER) has shown to improve postprandial metabolic systems and cognitive function, with superiority in dietary adherence compared with continuous energy restriction (CER)(1-3). A gap in current research is the impact of intermittent carbohydrate restriction (ICR) compared with IER in line with the carbohydrate-insulin model. Novel research (UEC 2019 008 FHMS) has explored the acute effects of ICR on postprandial metabolic systems and found engagement of the same underlying mechanisms with superior outcomes in glucose and lipid metabolism, compared with IER. Unpublished data supports the superiority of ICR over IER in dietary adherence due to perceived increased flexibility and reduced restrictions. However, a novel intermittent carbohydrate restricted diet has not been studied chronically, specifically exploring effects adherence and compliance on free living condition and its effect on body composition and food preference. This study primarily aims to explore the acceptability and compliance to ICR, and secondarily aims to explore its effect on behaviour change and body composition in free living condition in health adults. 40 participants (female and male) will follow a single arm novel intermittent carbohydrate diet protocol for 4 weeks. Weight, height, body fat %, waist circumference and resting energy expenditure values will be measured before and after the intervention. Compliance and the effects of dieting on the habitual food intake will be measured using food diaries and 24hr food recalls. Perceptions of participants' towards ICR and their experiences of dieting will be measured using questionnaires and an exit interview. This study will provide vital information for implementing flexible and adaptable dieting strategy, which can provide improvements to physical health in the long-term.

Conditions

• Healthy

Interventions

Type	Name	Description
BEHAVIORAL	Intermittent Carbohydrate Restriction (ICR) Protocol	A novel intermittent carbohydrate restriction (ICR) protocol involving two consecutive low-carbohydrate days (approximately 10% total energy from carbohydrate) followed by five non-restricted days per week, sustained over a 4-week period. Participants receive individualised dietary guidance and support materials to promote adherence in free-living conditions

Timeline

• Start date: 2023-01-13
• Primary completion: 2024-03-20
• Completion: 2024-04-20
• First posted: 2025-07-09
• Last updated: 2025-07-09

Locations

1 site across 1 country: United Kingdom