An Exploratory Study to Determine the Potential Impact of Parental Attendance at WW on Weight and Behavioural Outcomes in Children: WWChild

Parent Inclusion Criteria: 1. Male or female ages 18-75 years 2. Body Mass Index (BMI) of 25 to 45 (confirmed at baseline by researcher measurement) 3. Self report need to lose weight. Parent/primary care-giver to a child meeting child eligibility criteria 4. Willing to discontinue any current over-the-counter (OTC) supplements not recommended/prescribed by physician, with the exception of multivitamins or other vitamin supplement 5. Willing to follow recommendations required by study protocol (2 appointments), including attending programme workshops and using App if assigned to the WW arm 6. Use of a personal smartphone (iOS 9.0 or Android 4.1 or higher with at least 54MB of available storage for Android or 154 MB for iPhone to accommodate the size of the WW app) 7. Residing within 30 miles of a WW workshop 8. Ability to read, write and speak English at an adequate level to receive the intervention Child Inclusion Criteria 1. Must be at or over the 85th percentile (confirmed at baseline by researcher measurement) 2. Must be aged between 5 and 11 years at baseline 3. Must live with enrolled parent for the majority of the time Parent Exclusion Criteria: 1. Membership at WW within the past 12 months. 2. Given birth in the past six months, currently pregnant, or planning on becoming pregnant over the next 3 months. 3. Weight loss of ≥ 5 kg in the previous 6 months. 4. History of heart problems (e.g., angina, bypass surgery, myocardial infarction, etc.) within previous 6 months. 5. Untreated thyroid disease or any changes (type or dose) in thyroid medication in last 6 months. 6. Resting systolic blood pressure \>160 mmHg or resting diastolic blood pressure \>100 mmHg (asked as 'high blood pressure in on-line/telephone screen; confirmed at baseline visit) 7. Currently have type 1 or type II diabetes (pre-diabetes acceptable); 8. Currently have chronic/inflammatory gastrointestinal disorder (irritable bowel syndrome acceptable) 9. Reported health problems that make weight loss or unsupervised exercise unsafe or unreasonable (e.g., orthopedic limitations, heart problems) 10. Taking any prescription medication with known effects on appetite or weight (e.g., oral steroids, weight loss medications such as Qysmia, Contrave, with the exception of those on a stable dose of SSRIs for at least 6 months 11. Ever had surgical procedure for weight loss. 12. Major surgery within the previous 12 months. 13. Presence of implanted cardiac defibrillator or pacemaker. 14. History of cancer within past 5 years or current treatment for cancer (if skin cancer, past 6 months) 15. Currently have a medical diagnosis of Anorexia Nervosa or Bulimia Nervosa 16. Hospitalisation for psychiatric problems during the past 12 months 17. Planning to relocate in the next 12 months 18. Another member (excluding the enrolled child) of the household is participating in this research study Child Exclusion Criteria 1. Currently enrolled in any weight loss related programmes 2. Diagnosed with Prader- Willi syndrome, Cushing Syndrome, Hypothyroidism or Hashimoto's Disease. 3. Weight loss of ≥ 5% in the previous 6 months. 4. Untreated thyroid disease or any changes (type or dose) in thyroid medication in last 6 months. 5. Currently have type 1 or type II diabetes (pre-diabetes acceptable); 6. Currently have chronic/inflammatory gastrointestinal disorder (irritable bowel syndrome acceptable) 7. Reported health problems that make weight loss or unsupervised exercise unsafe or unreasonable (e.g., orthopedic limitations, heart problems) 8. Taking any prescription medication with known effects on appetite or weight. 9. Major surgery within the previous 12 months. 10. Presence of implanted cardiac defibrillator or pacemaker. 11. History of cancer within past 5 years or current treatment for cancer 12. Hospitalisation for psychiatric problems during the past 12 months 13. Another child of the household is participating in this research study \-