Playing devil's advocate, per your article, 3 in 100,000 children under 13 have an ED (c 0.003%). However, 30% of British children (25% boys, 33% girls) aged 2-19 are overweight or obese, and 75% of parents don't know what overweight looks like because it's become so normalised. What is the bigger problem?
You also say "Twelve per cent of the girls and 16 per cent of the boys had been teased at school because of their weight." and go on to say that half of these girls were now dieting, but that only a minority would be overweight- that doesnt tally with the fact that 33% girls of that age are overweight.
So, do they need self-esteem lessons? Probably not as much as they need PE lessons that are long enough for them to actually do something.