From the somnolent and perpetually hungry fat boy of Dickens's Pickwick Papersthrough Billy Bunter, Richards's bespectacled and much bullied “fat greedy owl of the Remove”, and onwards, obesity in childhood has been cruelly caricatured, stigmatised, and derided. Now, with an epidemic of obesity hitting Britain and the USA (and other countries), the serious medical consequences of childhood obesity are being better defined. An editorial by Ronald J Sokol in the Journal of Pediatrics (2000;136:711–13) lists some of these consequences in childhood: slipped capital femoral epiphysis, Blount disease, pseudotumour cerebri, sleep apnoea and hypoventilation, non-alcoholic steatohepatitis, polycystic ovary disease, type II diabetes, hyperlipidaemia, and hypertension. The consequences of obesity persisting into adult life are well known.  Three articles in the same issue are about non-alcoholic steatohepatitis. It has been estimated that up to 70% of obese adults have fatty infiltration of the liver and about a third of these have associated hepatic inflammation and fibrosis. Limited data suggest a similar problem in children. The 1988–94 US National Health and Nutrition Examination Survey (NHANES III) included 2450 children aged 12–18 years with serum liver enzyme concentrations recorded (Richard S Strauss and colleagues. Journal of Pediatrics 2000;136:727–33). Serum alanine aminotransferase (ALT) levels were raised in 10% of obese adolescents (odds ratio 6.7). Other factors associated with raised ALT in these subjects were moderate alcohol intake, raised levels of glycosylated haemoglobin or triglycerides, and low levels of vitamin E, β-carotene, and vitamin C.  In California (Joel E Lavine. Ibid:734–8), serum liver enzyme levels fell significantly in 11 obese children with raised enzymes and diffusely echogenic liver on ultrasound scan who were treated with oral vitamin E. In Italy (Pietro Vajro and colleagues. Ibid: 739–43), 31 children were treated with diet and ursodeoxycholic acid (UDCA). Liver enzyme abnormalities resolved in those who stuck to the diet and lost weight, but taking UDCA made no difference.  Childhood obesity presents many medical challenges. Lifestyle and dietary changes are needed in the population as a whole but prevention of obesity may prove difficult and ways to counter some of its most dire consequences are also needed. In his editorial, Ronald J Sokol calls for a new paediatric specialty of “obesitology”. Such specialists, he suggests, will need a “high tolerance for frustration”. There's no arguing with that.