The Effect of a Structured Weight-loss Programme on the Metabolic Profiles of Obese and Overweight Children

Aim: * The overall aims of this study to look at what changes are seen overweight and obese (very overweight) children, as they get thinner. * Specifically the investigators are interested in the chemicals and bacteria that children pass in their urine and stool because looking at how these change as it tells us about how their gut and other bodily systems are adapting. Hypothesis: Metabolic profiling is a useful and accurate tool for observing and monitoring weight loss in children Study plan: * To observe this weight loss process in children, the investigators will be attending a commercial weight loss camp called 'MORElife' which takes place every year in Leeds. This camp is attended by children age 8-17years who are overweight or obese, for between two and five weeks. It aims to help them lose weight through a structured diet, exercise, education and support program. * The investigators plan to, with the consent of the parent and agreement the child ask if they would kindly give us a urine sample at the beginning and end of their time on the camp. For those staying longer than 2 weeks the investigators will also ask for a sample in the middle if possible. * In addition for those children who consent, the investigators will also ask for a small stool (poo) sample at these same time points although there is no obligation to participate at all in the study and it will not affect their time on the camp whatever they decide. * Any children who will be attending the MORElife reunion (arranged by the camp at around 10-12 months after) who agree will be asked for a final urine and stool sample to look at the long-term effects. * Each sample is given a code so as to remain anonymous, frozen and transported to the university laboratory to be analyzed. * With permission and consent the investigators will also collect some information about the children such as, weight and height from the camp coordinators as well as samples of the diet that they will be fed and example