NCT06684834

Intermittent Carbohydrate Restriction in Cardiometabolic Health

The Effects of Intermittent Carbohydrate Restriction on Metabolic Health and Energy Balance in Adults with Abdominal Overweight and Obesity

• Status: Recruiting
• Phase: N/A
• Study type: Interventional
• Enrollment: 36 (estimated)
• Sponsor: University of Bath · Academic / Other
• Sex: All
• Age: 18 Years – 65 Years
• Healthy volunteers: Accepted

Summary

Metabolic conditions, such as heart disease, type 2 diabetes, and metabolic syndrome, are among the leading causes of disability and mortality worldwide. Identifying innovative lifestyle strategies to reduce metabolic risk remains a public health priority. Further research is essential to understand how low carbohydrate intake influences human metabolism and how intermittent carbohydrate restriction impacts weight loss and metabolic health markers. This study will investigate two interventions that restrict dietary carbohydrate intake on different schedules, examining their effects on metabolic health and energy balance in adults with abdominal overweight or obesity. The physiological mechanisms potentially underlying these effects will be explored by measuring a range of lifestyle and metabolic health parameters in both free-living and laboratory settings. A digital behaviour-change intervention will be incorporated after the dietary intervention to assess whether any metabolic effects can be sustained over time. The study employs a three-arm parallel-group design consisting of a two-week lifestyle monitoring phase, a four-week dietary intervention, and a four-week digital intervention, with four laboratory visits throughout each phase. During the dietary intervention, participants will be allocated to one of three groups: (i) carbohydrate restriction (\<8% of energy intake) on two consecutive days per week, (ii) carbohydrate restriction after 4 pm each day, or (iii) no dietary changes. Dietary intake, physical activity, and glucose levels will be monitored through wearable devices in free-living conditions. The digital intervention will use a mobile health application that provides individualised lifestyle recommendations and education based on data collected in free-living conditions. Laboratory-based measures will include anthropometry, body composition scans, indirect calorimetry, blood pressure monitoring, fat biopsies, and postprandial sampling of blood and expired air.

Conditions

• Obesity and Overweight

Interventions

Type	Name	Description
OTHER	5:2 carbohydrate restriction	Carbohydrate ingestion restricted to \<8% of energy intake on 2 self-selected consecutive days each week over 28-30 days. Ad libitum dietary amount, type and pattern followed on the remaining 5 days each week.
OTHER	Early time-restricted carbohydrate intake	Carbohydrate intake restricted to \<8% of energy intake after 4pm each day for 28 days. Ad libitum dietary amount, type and pattern followed before 4pm.

Timeline

• Start date: 2023-09-05
• Primary completion: 2025-10-01
• Completion: 2036-10-01
• First posted: 2024-11-12
• Last updated: 2024-11-12

Locations

1 site across 1 country: United Kingdom