Obesity in childhood is a global public health problem which continues to increase. It is associated with type 2 diabetes, high blood pressure, certain types of cancer, decreased psycho-social health and early mortality, among many other short- and long-term consequences. In many families where a child has obesity, at least one parent also has obesity or overweight with co-morbidity. In many cases, the care for children is more structured than for adults. Family treatment aimed at making lifestyle changes for the entire family, with those with obesity also restricting their calorie intake to normalize weight, has not been tested in Sweden and on a very limited scale internationally. International studies have shown that the more frequent the contact with healthcare, the better the results, regardless of the treatment method. However, frequent contacts are challenging to implement due to significant demands on both families and healthcare.

To address these challenges, the investigators aim to facilitate, improve, and optimize healthcare using a digital treatment support system involving daily home weighing and electronic communication between the clinic and families via a mobile application. The system is unique as it is based on real measurements, allowing both families and clinical staff to continuously monitor weight changes. This treatment involves fewer physical visits to the clinic but more frequent contact through the digital support system.

The goal is to evaluate whether a digital-physical family treatment conducted in primary care for families with at least one adult and one child with obesity leads to sustained weight loss with fewer visits, fewer missed appointments, resulting in more cost-effective care.

The investigators have evaluated a digital support system for childhood obesity. The result shows twice as good results for the children who used the system compared to a control group treated with usual care despite a low frequency of physical clinical visits.

The method involves behavioral change supported by a digital support system, including daily home weighing, a clear weight curve in a mobile app, and communication with the treatment team through the same app. Working with the support system means that, as a caregiver, one follows a clear manual. The core idea is that families, using a partially Motivational Interviewing-based communication approach, find their own ways to reduce excess weight in accordance with what the mobile app indicates. The healthcare provider offers information as needed but refrains from providing specific advice. Instead, the provider supports how to manage the changes. Treatment focuses on the parental role, setting boundaries, collaboration, conflict resolution, and avoiding self-deception.

Over six months, 8-12 families will undergo Family Treatment within primary care. The goal is to evaluate the treatment's effectiveness based on experiences from both families and caregivers, using surveys and semi-structured interviews after three and six months.

Inclusion Criteria:

• One or more children with obesity. Obesity defined based on the International Task Force criteria iso-BMI 30 and 35.
• At least one parent with obesity, i.e., BMI >30, or overweight with risk factors or comorbidity with a desire and willingness to lose weight.

Exclusion Criteria:

• Mental or physical illness in the child or parent that could seriously complicate the study's implementation.
• Serious language barriers preventing written communication in the digital support system.
• Separated parents where collaboration problems may complicate the study's implementation.
• Other reasons assessed to seriously complicate the study's implementation.

Using the evaluation from this study, we aim to optimize the family treatment method and finalize the application design based on user experiences for a larger randomized trial. as there are few individuals from a small place in Sweden, it will be difficult to keep the data anonymous.