Obesity is a worldwide problem, and the fact that it increasingly affects children and adolescents is worrying. The COVID-19 pandemic and the restrictions introduced affected the physical activity of children and adolescents, and changed their lifestyle and the amount of time spent in front of screens, which are significant factors correlated with weight gain. Due to the scale of the problem of obesity and overweight, much attention is currently paid to seeking effective forms of therapy in these different, difficult circumstances. Interventions promoting a healthy lifestyle among obese children after the COVID-19 pandemic are particularly important and necessary. This article provides a review of the literature on the recent worsening of obesity in the paediatric population, with particular emphasis on the importance of the COVID-19 pandemic. New methods of fighting obesity with the use of telemedicine and current methods of pharmacotherapy, including new drugs, are presented.