So information is the key – but do families really try to raise their children on vegan diets without being adequately informed? Sometimes, says Wilcock, they do – often because they are taken in by misleading information on the internet. And when a vegan diet starts to go wrong, the first symptom is usually that the child fails to thrive or grow properly. It's the shortage of calories and protein that kicks in first, she says, with rickets (caused by deficiencies in vitamin D and calcium) usually much further down the line. "Families are then referred to a dietician like me for advice – and every parent I've seen has been happy to make the changes I've recommended, because first and foremost they want their child to be healthy.