A leading expert in human nutrition has caused outrage by calling "over-fatness" a self-inflicted burden on the taxpayer.
Professor John Birkbeck, adjunct professor in human nutrition at Massey University, said anti-obesity efforts won't work until society refuses to accept the condition as normal and healthy, as it has done for smoking.
The 76-year-old, who moved into semi-retirement this week after 50 years in his field, rejected the notion that some people will get fat regardless of their efforts to keep weight down.
While acknowledging that some may have a genetic propensity to obesity, he said: "You can't get over-fat without eating more calories than you expend."
Birkbeck even cited concentration camps to illustrate his point.
"You do not see fat people in concentration camps. Why? Because they get hardly anything to eat and they have to do a lot of work."
Birkbeck also said "over-fatness" was a bigger problem with Maori and Pacific Islanders than Europeans and an emerging issue with Asian migrants.
His comments outraged groups working to reduce the obesity rate.
Maree Burns, coordinator of the Auckland-based Eating Difficulties Education Network, said they were "flagrant", "inappropriate", "intolerant" and "offensive".
"Shaming and blaming people has never been effective. This is the worst example of fat phobia and doesn't achieve anything except building discrimination," she said.
"People that are bigger already experience profound levels of discrimination and feel like health pariahs and social outcasts without these kinds of attitudes. With comments like that I am glad he's retiring."
She was particularly upset by his race-based comments.
"Maori and Pacific Islanders have bigger bone structures and bigger bodies. To use BMI and make comparisons across ethnic groups is inappropriate."
Birkbeck caused further outrage by saying methods used to reduce obesity rates had failed.
"In a dictatorship, you say 'everybody that comes back in a year's time with a Body Mass Index (BMI) of more than 30 will be shot' - and you'll find hardly anyone has a BMI over 30.
"But you can't do that in society, so what we have to do is find a way to cajole and coerce. And I don't think they've done enough of that."
Burns said that some people were destined to be fat and were "perfectly fine" at their body weights.
She said a lot of people were overweight as a result of constant dieting, which was unsustainable because it led to cravings and binge eating.
The way to curb obesity was to encourage a lifestyle change - which groups like hers were working to do.
Obesity Action Coalition director Leigh Sturgiss said the condition should be blamed on environment rather than the individual.
"While there is some aspect of people making choices for themselves, we do live in an environment that doesn't promote healthy eating," she said.
"I am quite surprised he is saying these things. I would have thought we were past these kinds of positions. He's quite controversial."