Cognitive Behavioral Therapy for Insomnia as an Adjunct to Time-restricted Eating on Weight Loss in Adults With Overweight or Obesity and Chronic Insomnia

Effects of Cognitive Behavioral Therapy for Insomnia (CBTI) as an Adjunct Intervention for Time-restricted Eating on Weight Loss in Adults With Overweight or Obesity and Chronic Insomnia

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.

Study Overview

• Status: Not yet recruiting
• Conditions: Chronic Insomnia; Overweight/Obesity
• Intervention / Treatment: Behavioral: Flexible Time-restricted eating group (FTRE); Behavioral: Flexible Time-restricted eating plus cognitive behavioural therapy for insomnia group (CBTI+FTRE)

Detailed Description

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

• Study Type: Interventional
• Enrollment (Estimated): 50
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Angus Pak-hung YU, PhD; Phone Number: (852) 39435253; Email: phayu@cuhk.edu.hk

Study Locations

• Hong Kong
  • Hong Kong, Hong Kong, 00000
    • Kwok Sports Building, The Chinese University of Hong Kong
    • Contact: Angus Pak-hung YU, PhD; Phone Number: (852) 39435253

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

1. Ethnic Chinese;
2. Age 18 years or older;

3. Fulfill the criteria of chronic insomnia defined by Diagnostic and Statistical Manual of Mental Disorders, 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.

4. With Overweight or obesity: BMI ≥ 23 kg/m2
5. Weight stable for the past 3 months
6. Habitual eating window ≥ 10 hours

Exclusion Criteria:

1. Known cardiovascular disease;
2. Type 1 or 2 diabetes mellitus;
3. Current use of GLP-1 receptor agonists or other prescription weight-loss medications within the past 3 months;
4. Currently on a special or prescribed diet for other reasons;
5. Currently receiving any psychological treatment for insomnia;
6. Previously received CBTI;
7. Night shift workers;
8. Breastfeeding, pregnant or trying to become pregnant;
9. Smokers.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Single

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Active Comparator: FTRE; Flexible Time-restricted Eating	Behavioral: Flexible Time-restricted eating group (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.
Experimental: CBTI+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); 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.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
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.	12 weeks, and 24 weeks

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Body mass index (BMI)	BMI will be calculated as weight in kilograms divided by the square of height in meters.	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.	12 weeks, and 24 weeks
Fat percentage	Fat percentage will be measured using a bioelectrical impedance analyzer (BIA).	12 weeks, and 24 weeks
Fat mass	Fat mass will be calculated as weight multiplied by fat percentage.	12 weeks, and 24 weeks
Fat free mass	Fat free mass will be calculated as weight subtracted by fat mass.	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.	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.	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.	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.	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.	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.	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.	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.	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.	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.	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.	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.	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.	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.	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.	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.	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.	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.	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.	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.	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.	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.	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.	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.	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.	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.	12 weeks, and 24 weeks

Collaborators and Investigators

• Sponsor: Chinese University of Hong Kong

Study record dates

Study Major Dates

• Study Start (Estimated): August 25, 2026
• Primary Completion (Estimated): June 30, 2027
• Study Completion (Estimated): June 30, 2027

Study Registration Dates

• First Submitted: August 14, 2026
• First Submitted That Met QC Criteria: August 14, 2026
• First Posted (Actual): August 18, 2026

Study Record Updates

• Last Update Posted (Actual): August 18, 2026
• Last Update Submitted That Met QC Criteria: August 14, 2026
• Last Verified: August 1, 2026

More Information

Terms related to this study

• Keywords: Chronic insomnia; Time-restricted eating; Cognitive Behavioural Therapy of Insomnia
• Additional Relevant MeSH Terms: Nervous System Diseases; Mental Disorders; Nutrition Disorders; Overnutrition; Body Weight; Sleep Wake Disorders; Sleep Disorders, Intrinsic; Dyssomnias; Pathological Conditions, Signs and Symptoms; Behavior; Nutritional and Metabolic Diseases; Signs and Symptoms; Feeding Behavior; Fasting; Overweight; Obesity; Sleep Initiation and Maintenance Disorders; Intermittent Fasting; Behavior Therapy; Psychotherapy; Behavioral Disciplines and Activities; Cognitive Behavioral Therapy
• Other Study ID Numbers: TRE_CBTI_1

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: UNDECIDED

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No