Lifestyle interventions are regarded as the therapy of choice in children with obesity. The efficiency of lifestyle intervention for childhood obesity has been proven by several randomized controlled trials and meta-analyses. Even a stable weight in a growing child with obesity is associated with an improvement in cardiovascular risk factors and comorbidities of obesity. In particular, children aged 5-12 years and children with overweight rather than obesity profit from lifestyle interventions. However, in clinical practice, the degree of weight loss with lifestyle intervention is only moderate, and the success rate 2 years after onset of an intervention is low (<10% with a decrease in BMI SD score of <0.25). Nevertheless, the difficulty of a child with overweight or obesity to reduce their weight might be attributable to not only a lack of motivation but also genetic background and/or adaptive changes in basal metabolic rate, hunger and satiety hormones that occur with weight loss. We must accept that lifestyle interventions are successful only in a subgroup of children with obesity. Regardless, the techniques used and the education of therapists need to be improved. If lifestyle interventions do not result in weight loss in a child with obesity, drug treatment to reduce cardiovascular risk factors should be initiated but is currently seldom performed.