A fat studies scholar wants people to avoid linking fatness to risk factors for COVID-19, claiming there's "little evidence".
Massey University Institute of Education senior lecturer Cat Pausé believes fat people are "thrown under the bus" when it comes to COVID-19.
Her new research, published in the International Journal of Disaster Risk Reduction, claims "questions remain about the quantitative risk of the association between fatness" and the coronavirus.
The research was carried out by Dr Pausé, Lesley Gray from Otago University's Primary Health Care and General Practice Department, and Otago Polytechnic's George Parker.
"It was important to us to highlight that fat people are being thrown under the bus yet again with the rhetoric and planning around COVID-19," said Dr Pausé.
"We know from the literature how fat people are often completely left out when making plans for natural hazards and disasters, and we see that implemented when they are left behind in real situations such as Hurricane Katrina."
She said this approach is "unjust and unethical".
"We wanted to take the opportunity to highlight that public health officials are throwing around fatness as a risk factor/death sentence for COVID with very little evidence."
But other researchers have said carrying extra weight could make it more likely for people to develop severe complications from the coronavirus.
"Outcomes for patients suffering from type 2 diabetes, heart disease, and high blood pressure are far worse than in otherwise healthy adults," said Aseem Malhotra, a cardiologist with the UK's NHS.
"What is not being spelled out is that poor diet and obesity are behind this," said Dr Malhotra, who carried out a study published in European Scientist last year.
In a study published in Science Magazine in September, Vermont University physician Anne Dixon said obesity "may be one reason for the devastating impact of COVID-19 in the United States".
"People with obesity are more likely than normal-weight people to have other diseases that are independent risk factors for severe COVID-19, including heart disease, lung disease, and diabetes," the study said.
Obese people also have weakened immunity, the study added.
ExerciseNZ chief executive Richard Beddie said exercise can help battle many health conditions.
"The early benefits of exercise include mental clarity, improved sleep and general positive state of mind. They will flow onto longer term health benefits such as cancer and cardiovascular disease reduction, through to significantly lower rates of degenerative diseases including dementia.
"Exercise really is the magic pill."
COVID-19, a respiratory disease, has killed more than 2 million people since emerging in the Chinese city of Wuhan in late 2019.