BackgroundNegative effects of COVID-19 lockdowns have been reported in adult patients with feeding and eating disorders (FED) whereas evidence of its impact on young clinical populations is still limited and somewhat inconsistent. The present study aims to investigate the effect of the first COVID-19 lockdown on a range of FED symptoms in children and adolescents: (a) already receiving treatment in our specialist service for FED when the pandemic hit, and (b) prospectively evaluated in our service from October 2020 to July 2021.MethodsOut of sixty-one eligible patients with a broad spectrum of FED invited, forty-five young patients (aged 11–18) consented to participate and were included. An ad-hoc survey, consisting of open questions, multiple choice questions, yes/no questions, and a symptoms checklist, was administered online.ResultsAbout half of the participants (46.7%) reported a positive effect of lockdown on FED symptomatology. Patients with anorexia nervosa (AN) reported the highest rate of symptomatology worsening (58.6%). Younger patients (11–13 years) showed a greater improvement of symptoms compared to older ones (14–18 years of age). COVID-19 lockdown was identified as the precipitating factor for FED onset in 60.7% of newly evaluated patients.ConclusionsEvidence from our investigation points out that although the COVID-19 pandemic was a precipitating factor for a FED for many active and newly referred patients, it had a positive impact on youth who were already in treatment and younger participants.Supplementary InformationThe online version contains supplementary material available at 10.1186/s40337-023-00792-1.