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NCT Number: NCT07770516

Cognitive Behavioral Therapy for Insomnia as an Adjunct to 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.

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Key information

Conditions

Chronic Insomnia Behavior Body Weight Dyssomnias Fasting Feeding Behavior Intermittent Fasting Mental Disorders Nervous System Diseases Nutrition Disorders Nutritional and Metabolic Diseases Obesity Overnutrition Overweight Overweight/Obesity Pathological Conditions, Signs and Symptoms Signs and Symptoms Sleep Disorders, Intrinsic Sleep Initiation and Maintenance Disorders Sleep Wake Disorders

Age range

18 year and older

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

Kwok Sports Building, The Chinese University of Hong Kong

Hong Kong, 00000

Location contact

Angus Pak-hung YU, PhD

CONTACT

(852) 39435253

About this study

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

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Ethnic Chinese;
  • Age 18 years or older;
  • 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.

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

Exclusion criteria

  • 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;
  • Currently receiving any psychological treatment for insomnia;
  • Previously received CBTI;
  • Night shift workers;
  • Breastfeeding, pregnant or trying to become pregnant;
  • Smokers.

Treatment and study plan

Flexible Time-restricted eating group (FTRE)

Behavioral

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.

Flexible Time-restricted eating plus cognitive behavioural therapy for insomnia group (CBTI+FTRE)

Behavioral

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.

Primary outcomes

  1. Weight

    Time frame: 12 weeks, and 24 weeks

    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

  1. Body mass index (BMI)

    Time frame: 12 weeks, and 24 weeks

    BMI will be calculated as weight in kilograms divided by the square of height in meters.

  2. Waist circumference

    Time frame: 12 weeks, and 24 weeks

    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.

  3. Fat percentage

    Time frame: 12 weeks, and 24 weeks

    Fat percentage will be measured using a bioelectrical impedance analyzer (BIA).

  4. Fat mass

    Time frame: 12 weeks, and 24 weeks

    Fat mass will be calculated as weight multiplied by fat percentage.

  5. Fat free mass

    Time frame: 12 weeks, and 24 weeks

    Fat free mass will be calculated as weight subtracted by fat mass.

  6. Insomnia Severity Index (ISI)

    Time frame: 12 weeks, and 24 weeks

    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.

  7. Pittsburgh Sleep Quality Index (PSQI)

    Time frame: 12 weeks, and 24 weeks

    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.

  8. Actigraphy-estimated sleep onset latency

    Time frame: 12 weeks, and 24 weeks

    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.

  9. Actigraphy-estimated total sleep time

    Time frame: 12 weeks, and 24 weeks

    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.

  10. Actigraphy-estimated wake time after sleep onset

    Time frame: 12 weeks, and 24 weeks

    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.

  11. Actigraphy-estimated sleep efficiency

    Time frame: 12 weeks, and 24 weeks

    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. Actigraphy-estimated number of awakenings

    Time frame: 12 weeks, and 24 weeks

    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.

  13. Actigraphy-estimated average awaken time

    Time frame: 12 weeks, and 24 weeks

    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.

  14. Sleep diary-estimated sleep onset latency

    Time frame: 12 weeks, and 24 weeks

    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.

  15. Sleep diary-estimated total sleep time

    Time frame: 12 weeks, and 24 weeks

    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.

  16. Sleep diary-estimated wake time after sleep onset

    Time frame: 12 weeks, and 24 weeks

    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.

  17. Sleep diary-estimated sleep efficiency

    Time frame: 12 weeks, and 24 weeks

    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.

  18. Sleep diary-estimated number of awakenings

    Time frame: 12 weeks, and 24 weeks

    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.

  19. Sleep diary-estimated average awaken time

    Time frame: 12 weeks, and 24 weeks

    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.

  20. Habitual physical activity (Total volume of physical activity, MET-minutes/week)

    Time frame: 12 weeks, and 24 weeks

    The Chinese version of the International Physical Activity Questionnaire, Long Form (IPAQ-LC), will be used to assess the activity levels of the participants.

  21. Habitual physical activity (Total sedentary time, hours/week)

    Time frame: 12 weeks, and 24 weeks

    The Chinese version of the International Physical Activity Questionnaire, Long Form (IPAQ-LC), will be used to assess the activity levels of the participants.

  22. Systolic blood pressure

    Time frame: 12 weeks, and 24 weeks

    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.

  23. Diastolic blood pressure

    Time frame: 12 weeks, and 24 weeks

    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.

  24. Appetite (Hunger)

    Time frame: 12 weeks, and 24 weeks

    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.

  25. Appetite (Satiety)

    Time frame: 12 weeks, and 24 weeks

    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.

  26. Food intake (Total energy intake)

    Time frame: 12 weeks, and 24 weeks

    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.

  27. Food intake (Carbohydrate consumption)

    Time frame: 12 weeks, and 24 weeks

    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.

  28. Food intake (Protein consumption)

    Time frame: 12 weeks, and 24 weeks

    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.

  29. Food intake (Fat consumption)

    Time frame: 12 weeks, and 24 weeks

    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.

  30. Eating window

    Time frame: 12 weeks, and 24 weeks

    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.

  31. Exercise habit

    Time frame: 12 weeks, and 24 weeks

    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.

Study contacts

Contact information is provided by the study sponsor or research team.

Angus Pak-hung YU, PhD

CONTACT

[email protected]

(852) 39435253

Sponsors and collaborators

Lead sponsor

Chinese University of Hong Kong

Other

Registry information

Official study title

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

Important dates

Study start
2026
Primary completion
2027
Study completion
2027
First posted
Aug 18, 2026
Registry last updated
Aug 18, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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