Is child obesity a child protection issue?

Failure to thrive in early childhood is an important health and social issue with laws requiring parents to provide the necessities of life (NZ Crimes Act 1961).
New Zealand has its own examples where parents have been reported for failing to administer treatment for their children or for rejecting professional advice regarding their child’s health and welfare. These include Liam Williams – Holoway, Tovia Laufau and Caleb Moorhead.
With severe childhood obesity increasing in prevalence and clear links between obesity and both acute and chronic health implications, is it possible to view extreme cases of obesity as a form of failing to thrive and, as such a case of parental neglect?
If parents of severely obese children seem unwilling or unable to help their children adhere to weight loss and nutrition programmes, should social services such as Child Youth and Family (CYFS) be notified? Should children be protected from severe obesity?