The primary objective of the proposed study is to develop, deliver and assess the feasibility and adherence to a targeted behavioral sleep intervention for sleep impaired obese patients.

Secondary objectives are to demonstrate that a targeted behavioral sleep intervention can improve treatment outcomes in obese adult outpatients enrolled to a lifestyle and dietary modification program; and to demonstrate that a targeted behavioral sleep intervention enhances the long-term maintenance of treatment gains in obese adults enrolled in a lifestyle and dietary modification program.

Those with sleep impairment (sleep duration of ≤6.5hours per 24-hours; and/or poor sleep quality [<85% efficiency]; and/or misaligned nocturnal sleep timing [>03:00 on weekdays]) who are also obese (Body Mass Index [BMI] ≥27.5 kg/m2) will be recruited and randomized to a 12-week weight loss intervention with/without sleep improvement. Volunteers will be followed for a further six months to assess multiple outcome measures.

It is hypothesised that inclusion of a targeted behavioral sleep improvement intervention will be feasible and acceptable and will enhance immediate and long-term treatment outcomes of obese adults enrolled to a lifestyle and dietary modification program. The results of the study will be used to better inform the design and development of a future Randomized Controlled Trial (RCT).

Sleep improvement may be incorporated into weight management treatments as a cost-effective alternative/addition.

The primary objective of the proposed study is to develop, deliver and assess the feasibility and adherence to a targeted behavioral sleep intervention for sleep impaired obese patients.

Secondary objectives are to demonstrate that a targeted behavioral sleep intervention can improve treatment outcomes in obese adult outpatients enrolled to a lifestyle and dietary modification program; and to demonstrate that a targeted behavioral sleep intervention enhances the long-term maintenance of treatment gains in obese adults enrolled in a lifestyle and dietary modification program.

Those with sleep impairment (sleep duration of ≤6.5hours per 24-hours; and/or poor sleep quality [<85% efficiency]; and/or misaligned nocturnal sleep timing [>03:00 on weekdays]) who are also obese (Body Mass Index [BMI] ≥27.5 kg/m2) will be recruited and randomized to a 12-week weight loss intervention (based on a previously developed specialist lifestyle management program) with/without sleep improvement (based on a cognitive behaviour treatment developed to treatment sleep problems in US military). Volunteers will be followed for a further six months to assess multiple outcome measures. Other secondary measures to be assessed are mood (Hospital Anxiety Depression Scale [HADS], food intake (24-hour food recall), quality of life (IWQOL-LITE & EQ-5D), and sleep (PSQI & RU_SATED), all of which will be assessed using validated questionnaires that have been previously assessed for reliability.

It is hypothesised that inclusion of a targeted behavioral sleep improvement intervention will be feasible and acceptable and will enhance immediate and long-term treatment outcomes of obese adults enrolled to a lifestyle and dietary modification program. The results of the study will be used to better inform the design and development of a future Randomized Controlled Trial (RCT).

Sleep improvement may be incorporated into weight management treatments as a cost-effective alternative/addition.

Inclusion Criteria:

• Sleep impaired individuals defined as meeting one or more of the following objectively estimated sleep feature: 1) ≤6.5hours per 24-hours; 2) poor sleep quality (<85% efficiency); 3) misaligned nocturnal sleep timing (>03:00 on weekdays);
• Obese (BMI ≥27.5 kg/m2 for Asians/Arabs or BMI ≥30.0 kg/m2 for Europeans/Caucasians);
• Men/women;
• Age 18-50 years (upper age limit chosen due to specific alterations in sleep duration and quality commonly observed after this age);
• Good English language comprehension/communication skills;
• Able to provide informed consent and willing to participate in the study.

Exclusion Criteria:

• Currently taking medication(s) that may interfere with weight loss (e.g. corticosteroids);
• Contraindications to use of the Cambridge Weight Plan (heart attack or stroke three months preceding study participation; lactose intolerance; gallstones; porphyria; active gout);
• Medications that may interfere with sleep;
• Clinically diagnosed sleep disorder(s) or those at high risk of undiagnosed OSA based on three questionnaires (Berlin, ESS, STOP-BANG);
• Chronic illness (asthma, COPD, diabetes, arthritis, fibromyalgia, heart condition, kidney or liver disease);
• Uncontrolled hypertension;
• Polycystic ovary syndrome;
• Endocrine disorder(s), except for stable treated hypothyroidism;
• Psychiatric disorder(s), except for stable treated depression;
• Currently taking monoamine oxidase inhibitor medication;
• Previous/planned bariatric surgery;
• Diagnosed eating disorders;
• Night-shift workers;
• Substance use;
• Excessive alcohol consumption;
• Known pregnancy or planned pregnancy during the study/breastfeeding or given birth in last 3 months;
• Family circumstances e.g. infants, young children, pets that will make study adherence difficult.

IPD will only be shared with researchers within the same research team who are listed on the approval ethics application

This information will be shared with other members of the research team who are approved on the ethics application. The information will be available to the research team throughout the course of the study.

The master file will be retained by the PI and stored on a password-protected computer. Access will only be permitted to other members of the research team for study related activities.