About this trial
Obesity (being overweight due to excess body fat) is a common health condition that increases the risk of developing problems such as diabetes, high blood pressure, and heart disease. Time-restricted eating (TRE), which involves eating all meals within a set period each day, has become a popular and simple approach for weight management. However, not everyone achieves the same results from TRE. Research suggests that poor sleep and chronic insomnia can increase hunger, affect food choices, and lead to higher calorie intake, which may make weight loss more difficult.
This study aims to examine whether improving sleep can enhance the effectiveness of flexible time-restricted eating (FTRE) for weight loss. Participants will receive either FTRE alone or FTRE combined with Cognitive Behavioural Therapy for Insomnia (CBTI), a well-established treatment for chronic insomnia. By comparing these two approaches, this study will help determine whether addressing sleep problems can improve weight management outcomes in individuals with overweight or obesity and chronic insomnia. The findings may contribute to the development of more effective and comprehensive lifestyle programmes for improving both sleep and weight-related health.
Eligibility criteria
This trial does not accept healthy volunteersQualifiers
Ethnic Chinese;
Age 18 years or older;
With Overweight or obesity: BMI ≥ 23 kg/m2
Weight stable for the past 3 months
Disqualifiers
Known cardiovascular disease;
Type 1 or 2 diabetes mellitus;
Current use of GLP-1 receptor agonists or other prescription weight-loss medications within the past 3 months;
Currently on a special or prescribed diet for other reasons;
Trial design
Parallel
Treatments tested in this trial
Flexible Time-restricted eating group (FTRE)
BehavioralParticipants assigned to the FTRE group will be instructed to follow a 16:8 time-restricted eating schedule, consuming food ad libitum within an 8-hour eating window and fasting for the remaining 16 hours of the day. No restrictions will be placed on the type or quantity of foods consumed during the eating window, and participants will not be required to track their energy intake. During fasting periods, participants will be encouraged to maintain adequate hydration by drinking water and may also consume non-caloric beverages, such as plain tea or black coffee. Participants will be allowed to select their preferred 8-hour eating window, provided it begins between 8:00 AM and 12:00 PM and ends between 4:00 PM and 8:00 PM.
Flexible Time-restricted eating plus cognitive behavioural therapy for insomnia group (CBTI+FTRE)
BehavioralIn addition to following the TRE instruction in the TRE group, participants in the CBTI+TRE group will also participate in a 12-week group-based CBTI intervention with biweekly 90-minute sessions. The intervention comprises all CBTI elements, including sleep hygiene, sleep restriction, stimulus control, cognitive restructuring, and stress and relaxation techniques. Intervention will be delivered by trained research personnel.
Treatment groups
Trial outcomes
Primary outcomes
Weight
Body weight will be measured using a bioelectrical impedance analyzer (BIA) to the nearest 0.1 kg following a minimum 4-hour fast. Participants will be instructed to void their bladder immediately before the assessment, remove their shoes and heavy clothing, and stand upright on the analyzer platform during the measurement.
Secondary outcomes
Body mass index (BMI)
BMI will be calculated as weight in kilograms divided by the square of height in meters.
Waist circumference
Waist circumference will be measured using the protocol of World Health Organisation (i.e. the circumference at the midpoint between the lower margin of the last palpable rib and the top of the iliac crest). Waist circumference will be measured to the nearest 0.1cm.
Fat percentage
Fat percentage will be measured using a bioelectrical impedance analyzer (BIA).
Fat mass
Fat mass will be calculated as weight multiplied by fat percentage.
Sponsors and contacts
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