Around the world, the amount of people who are overweight is increasing. This has become a public health crisis. Obesity, especially in children, is a problem because it is associated with risk for health problems and psychological issues. These problems include heart disease and poor quality of life and can happen both in childhood and later life.

Programs that help people change their lifestyle and behaviour are effective to help people lose weight and improve their mental health. In children, the main issue for treating obesity is to help the child keep weight off and to prevent a return to unhealthy behaviours. This means that long-term support is needed. But the health care system is not set up to do this because of a limited amount of resources. The aim of this study is to see if there are better long-term results if we use a technology tool along with a lifestyle program.

The aim of this study is to examine a personal digital assistant (PDA) program (Text2bHealthy) supplemented to an existing family-based group treatment for overweight and obese children. This treatment is called the British Columbia Centre for Healthy Weights (BCCHW) Shapedown BC program. The aim of this study is to see if Text2bHealthy supplemented to the Shapedown BC program helps children to keep the weight of and improves physical activity as well as fruit, vegetable, and fat intake.

We know from studies that reporting one's own behaviour, goal setting, and tailored feedback are key elements in changing health behaviours. Text2bHealthy includes these key elements. PDAs will be given to 30 10-16 year old children and adolescents after completing the Shapedown BC program. They will be explained how to use the PDA. Children who participate in the Text2bHealthy program will set weekly goals related to their physical activity, eating or sitting behaviours. Also, they will report on their lifestyle behaviours twice a week. They will receive personalized feedback on their progress. The feedback is designed to be supportive and to reinforce their behaviour in a positive way. The control group (N=30) will use a paper dairy to keep track of their lifestyle behaviours. At 0 and 3 months after completing the Shapedown BC program, measurements such as height and weight will be taken. Also, exercise and nutrition behaviour will be measured. Physical activity will be measured with pedometers and a recall and nutrition intake with questionnaires.

Because it is hard to maintain weight loss, we need to provide programs that offer the long-term support of behaviour change. Tools such as PDAs seem to be ideal to offer long-term support. For the purpose of this study, PDAs will be used as a proof of concept; the programming can be incorporated into smart phones in the future. From previous studies we know that reporting one's own behaviour seems to improve weight loss in children. Also, behaviours are more likely to be reported when using mobile phones compared to paper \& pencil diaries. I am one of the first to study the effect of innovative technologies by using self-reporting, goal setting, and personalized feedback in childhood obesity treatment. We hope that the results from this study will increase our knowledge on the use and feasibility of digital devices in childhood obesity treatment.

The outcomes of this research will be used to better understand how to improve weight loss maintenance among obese children. Obesity places children at higher risk for heart disease and poor quality of life when they are adults. Thus time and cost-effective long-term support programs need to be developed to improve weight loss maintenance. This new program has the potential to improve maintenance of weight loss and healthy lifestyle in overweight and obese children and adolescents.