An interventional study of Flexible Time-restricted eating group (FTRE) and Flexible Time-restricted eating plus cognitive behavioural therapy for insomnia group (CBTI+FTRE) in Chronic Insomnia and Overweight/Obesity, sponsored by Chinese University of Hong Kong. Not yet recruiting at 1 site in Hong Kong. Open to participants aged 18 Years and older. Per ClinicalTrials.gov, last updated 2026-08-18.
Sponsored by Chinese University of Hong Kong · Not applicable, Interventional, and Treatment
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.
This study aims to investigate whether CBTI can enhance the effectiveness of TRE for weight control in adults with chronic insomnia and overweight or obesity. This assessor-blinded, two-arm, parallel-group randomized controlled pilot trial plans to recruit 50 Chinese adults aged 18 years or older with chronic insomnia and overweight or obesity (BMI ≥23 kg/m²) in Hong Kong. Participants will be randomized (1:1) to a flexible time-restricted eating group (FTRE, n=25) or a flexible time-restricted eating plus CBTI group (CBTI+FTRE, n=25). Both groups will follow a 16:8 time-restricted eating schedule for 12 weeks, while participants in the CBTI+FTRE group will additionally receive a 12-week group-based CBTI program consisting of biweekly 90-minute sessions. Assessments will be conducted at baseline, post-intervention (week 12), and follow-up (week 24). The primary outcome is body weight. Secondary outcomes include body mass index, waist and neck circumferences, body composition, insomnia severity, sleep quality, objective and subjective sleep parameters, physical activity, blood pressure, appetite, food intake, eating window, and exercise habits. We hypothesize that the addition of CBTI to TRE will result in greater weight loss and improved sleep outcomes compared with TRE alone
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Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
Fulfill the criteria of chronic insomnia defined by , Fifth Edition, Text Revision (DSM-5-TR) , which are:
i. manifestation of predominant, subpar sleep quantity or quality; ii. exhibition of any sleep difficulties ranging from sleep initiation, sleep maintenance to early awakening with the inability to restore sleep.
iii. concomitant presentation of significant distress or impairment, including fatigue or low energy, cognitive impairment, mood disturbance, behavioral problems, impaired occupational or academic functioning, impaired interpersonal or social functioning and negative impact on caregiver or family functioning; iv. sleep difficulty occurs at least three nights per week; v. sleep difficulty has been persistent for at least three months; and vi. sleep difficulty is not affected regardless of adequate opportunity given for sleep.
Exclusion Criteria:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
The American Psychiatric Association’s manual of mental health diagnoses. DSM-5 (2013, revised as DSM-5-TR in 2022) replaced DSM-IV, and some studies still name the older edition. “Meets DSM criteria for …” means diagnosed by that edition’s diagnostic criteria, usually by a clinician in an interview.
Weight in kilograms divided by height in metres squared. Example: 70 kg and 1.75 m gives 70 ÷ (1.75 × 1.75) ≈ 22.9.
What counts as overweight or obesity differs between countries (some use lower cut-offs), so go by the range the study states.
DSM diagnostic criteria
The American Psychiatric Association’s manual of mental health diagnoses. DSM-5 (2013, revised as DSM-5-TR in 2022) replaced DSM-IV, and some studies still name the older edition. “Meets DSM criteria for …” means diagnosed by that edition’s diagnostic criteria, usually by a clinician in an interview.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
BMI (body mass index)
Weight in kilograms divided by height in metres squared. Example: 70 kg and 1.75 m gives 70 ÷ (1.75 × 1.75) ≈ 22.9.
What counts as overweight or obesity differs between countries (some use lower cut-offs), so go by the range the study states.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Flexible Time-restricted Eating
Behavioral: Flexible Time-restricted eating group (FTRE)
Flexible Time-restricted Eating plus Cognitive Behavioural Therapy for Insomnia
Behavioral: Flexible Time-restricted eating plus cognitive behavioural therapy for insomnia group (CBTI+FTRE)
Participants 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.
In 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.
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.
Time frame: 12 weeks, and 24 weeks
Body mass index (BMI)
BMI will be calculated as weight in kilograms divided by the square of height in meters.
Time frame: 12 weeks, and 24 weeks
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.
Time frame: 12 weeks, and 24 weeks
Fat percentage
Fat percentage will be measured using a bioelectrical impedance analyzer (BIA).
Time frame: 12 weeks, and 24 weeks
Fat mass
Fat mass will be calculated as weight multiplied by fat percentage.
Time frame: 12 weeks, and 24 weeks
Fat free mass
Fat free mass will be calculated as weight subtracted by fat mass.
Time frame: 12 weeks, and 24 weeks
Insomnia Severity Index (ISI)
The ISI, a commonly used instrument in clinical settings, will be used to assess the perceived insomnia severity. It consists of seven items to evaluate sleep onset, sleep maintenance, early awakening, satisfaction with the current sleep pattern, impairment of daily functioning due to sleep, noticeable impairment due to sleep problems, degree of distress and concerns caused by sleep problems. Each item is rated on a "0-4" Likert scale, resulting in a range of scores between 0 and 28. The higher the score, the higher the perceived severity.
Time frame: 12 weeks, and 24 weeks
Pittsburgh Sleep Quality Index (PSQI)
Subjective sleep quality will be evaluated using the PSQI. The PSQI assesses 7 components of subjective sleep quality, including self-reported sleep quantity, use of sleep medication, and disturbances of sleep, and is considered one of the most frequently used assessments of subjective sleep quality. The total score of the PSQI ranges from 0 to 21, where lower values indicate better sleep.
Time frame: 12 weeks, and 24 weeks
Actigraphy-estimated sleep onset latency
Participants will be instructed to wear a wrist actigraph device (wGT3X-BT, ActiGraph) on their non-dominant wrists 24 hours for 7 days to measure objective sleep. This device is a 3-axis accelerometer that estimates wakefulness and sleep based on detected movements. The 7-day average of objective sleep parameters (i.e. sleep onset latency) will be estimated by the data in the actigraphy record.
Time frame: 12 weeks, and 24 weeks
Actigraphy-estimated total sleep time
Participants will be instructed to wear a wrist actigraph device (wGT3X-BT, ActiGraph) on their non-dominant wrists 24 hours for 7 days to measure objective sleep. This device is a 3-axis accelerometer that estimates wakefulness and sleep based on detected movements. The 7-day average of objective sleep parameters (i.e. total sleep time) will be estimated by the data in the actigraphy record.
Time frame: 12 weeks, and 24 weeks
Actigraphy-estimated wake time after sleep onset
Participants will be instructed to wear a wrist actigraph device (wGT3X-BT, ActiGraph) on their non-dominant wrists 24 hours for 7 days to measure objective sleep. This device is a 3-axis accelerometer that estimates wakefulness and sleep based on detected movements. The 7-day average of objective sleep parameters (i.e. wake time after sleep onset) will be estimated by the data in the actigraphy record.
Time frame: 12 weeks, and 24 weeks
Actigraphy-estimated sleep efficiency
Participants will be instructed to wear a wrist actigraph device (wGT3X-BT, ActiGraph) on their non-dominant wrists 24 hours for 7 days to measure objective sleep. This device is a 3-axis accelerometer that estimates wakefulness and sleep based on detected movements. The 7-day average of objective sleep parameters (i.e. sleep efficiency) will be estimated by the data in the actigraphy record.
Time frame: 12 weeks, and 24 weeks
Actigraphy-estimated number of awakenings
Participants will be instructed to wear a wrist actigraph device (wGT3X-BT, ActiGraph) on their non-dominant wrists 24 hours for 7 days to measure objective sleep. This device is a 3-axis accelerometer that estimates wakefulness and sleep based on detected movements. The 7-day average of objective sleep parameters (i.e. number of awakenings) will be estimated by the data in the actigraphy record.
Time frame: 12 weeks, and 24 weeks
Actigraphy-estimated average awaken time
Participants will be instructed to wear a wrist actigraph device (wGT3X-BT, ActiGraph) on their non-dominant wrists 24 hours for 7 days to measure objective sleep. This device is a 3-axis accelerometer that estimates wakefulness and sleep based on detected movements. The 7-day average of objective sleep parameters (i.e. average awaken time) will be estimated by the data in the actigraphy record.
Time frame: 12 weeks, and 24 weeks
Sleep diary-estimated sleep onset latency
Participants will be instructed to record their sleep pattern, including on-bed time, leave bed time, total sleep time and the number of awakenings, for 7 days on a sleep diary while wearing the actigraph device. The 7-day average of subjective sleep parameters (i.e. sleep onset latency) will be estimated by the sleep diary record.
Time frame: 12 weeks, and 24 weeks
Sleep diary-estimated total sleep time
Participants will be instructed to record their sleep pattern, including on-bed time, leave bed time, total sleep time and the number of awakenings, for 7 days on a sleep diary while wearing the actigraph device. The 7-day average of subjective sleep parameters (i.e. total sleep time) will be estimated by the sleep diary record.
Time frame: 12 weeks, and 24 weeks
Sleep diary-estimated wake time after sleep onset
Participants will be instructed to record their sleep pattern, including on-bed time, leave bed time, total sleep time and the number of awakenings, for 7 days on a sleep diary while wearing the actigraph device. The 7-day average of subjective sleep parameters (i.e. wake time after sleep onset) will be estimated by the sleep diary record.
Time frame: 12 weeks, and 24 weeks
Sleep diary-estimated sleep efficiency
Participants will be instructed to record their sleep pattern, including on-bed time, leave bed time, total sleep time and the number of awakenings, for 7 days on a sleep diary while wearing the actigraph device. The 7-day average of subjective sleep parameters (i.e. sleep efficiency) will be estimated by the sleep diary record.
Time frame: 12 weeks, and 24 weeks
Sleep diary-estimated number of awakenings
Participants will be instructed to record their sleep pattern, including on-bed time, leave bed time, total sleep time and the number of awakenings, for 7 days on a sleep diary while wearing the actigraph device. The 7-day average of subjective sleep parameters (i.e. number of awakenings) will be estimated by the sleep diary record.
Time frame: 12 weeks, and 24 weeks
Sleep diary-estimated average awaken time
Participants will be instructed to record their sleep pattern, including on-bed time, leave bed time, total sleep time and the number of awakenings, for 7 days on a sleep diary while wearing the actigraph device. The 7-day average of subjective sleep parameters (i.e. average awaken time) will be estimated by the sleep diary record.
Time frame: 12 weeks, and 24 weeks
Habitual physical activity (Total volume of physical activity, MET-minutes/week)
The Chinese version of the International Physical Activity Questionnaire, Long Form (IPAQ-LC), will be used to assess the activity levels of the participants.
Time frame: 12 weeks, and 24 weeks
Habitual physical activity (Total sedentary time, hours/week)
The Chinese version of the International Physical Activity Questionnaire, Long Form (IPAQ-LC), will be used to assess the activity levels of the participants.
Time frame: 12 weeks, and 24 weeks
Systolic blood pressure
Blood pressure will be measured in accordance with the American Heart Association's scientific statement on blood pressure assessment in humans. Participants will be instructed to sit quietly with their back supported, feet flat on the floor, and legs uncrossed. After resting in this position for 5 minutes, measurements will be taken using an electronic blood pressure monitor. During the procedure, the participant's right upper arm will be supported at heart level on a flat surface, and they will be asked to refrain from talking throughout both the resting period and the measurement. Two readings of systolic blood pressure will be obtained, spaced 2 minutes apart, and the average of the two measurements will be recorded as the final blood pressure reading. If the difference between the two measurements exceeds 5 mmHg, an additional reading will be taken, and the average of all three readings will be used as the final measurement.
Time frame: 12 weeks, and 24 weeks
Diastolic blood pressure
Blood pressure will be measured in accordance with the American Heart Association's scientific statement on blood pressure assessment in humans. Participants will be instructed to sit quietly with their back supported, feet flat on the floor, and legs uncrossed. After resting in this position for 5 minutes, measurements will be taken using an electronic blood pressure monitor. During the procedure, the participant's right upper arm will be supported at heart level on a flat surface, and they will be asked to refrain from talking throughout both the resting period and the measurement. Two readings of diastolic blood pressure will be obtained, spaced 2 minutes apart, and the average of the two measurements will be recorded as the final blood pressure reading. If the difference between the two measurements exceeds 5 mmHg, an additional reading will be taken, and the average of all three readings will be used as the final measurement.
Time frame: 12 weeks, and 24 weeks
Appetite (Hunger)
Subjective hunger will be assessed using validated 100-mm Visual Analogue Scales (VAS) administered upon waking, before and 30 minutes after the first and last meals, and before bedtime. Higher scores will indicate greater perceived hunger.
Time frame: 12 weeks, and 24 weeks
Appetite (Satiety)
Subjective satiety will be assessed using validated 100-mm Visual Analogue Scales (VAS) administered upon waking, before and 30 minutes after the first and last meals, and before bedtime. Higher scores will indicate greater perceived fullness.
Time frame: 12 weeks, and 24 weeks
Food intake (Total energy intake)
Participants will be instructed to complete a consecutive 3-day food diary, including 2 weekdays and 1 weekend day. Total energy intake will be estimated based on the dietary records.
Time frame: 12 weeks, and 24 weeks
Food intake (Carbohydrate consumption)
Participants will be instructed to complete a consecutive 3-day food diary, including 2 weekdays and 1 weekend day. Carbohydrate consumption will be estimated based on the dietary records.
Time frame: 12 weeks, and 24 weeks
Food intake (Protein consumption)
Participants will be instructed to complete a consecutive 3-day food diary, including 2 weekdays and 1 weekend day. Protein consumption will be estimated based on the dietary records.
Time frame: 12 weeks, and 24 weeks
Food intake (Fat consumption)
Participants will be instructed to complete a consecutive 3-day food diary, including 2 weekdays and 1 weekend day. Fat consumption will be estimated based on the dietary records.
Time frame: 12 weeks, and 24 weeks
Eating window
Participants will be required to record the start time of their first caloric intake and the end time of their last caloric intake in the seven-day log. The eating window will be calculated as the time interval between the first and last eating occasions of the day.
Time frame: 12 weeks, and 24 weeks
Exercise habit
Participants will be instructed to complete a 7-day exercise log. The log will capture information on all exercise activities undertaken during the weeks, including the date, start and end times, exercise type, and exercise intensity.
Time frame: 12 weeks, and 24 weeks
Plan to share: Undecided
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