It is an image of obese people that visiting Open University (United Kingdom) Health Psychology Professor Wendy Stainton Rogers is trying to change.
Stigmatism of overweight people came from many quarters of society, she said.
From an early age, people's views of the obese were shaped by children's books, which depicted obese people as "ugly and bad", she said.
A recent article in The Sun newspaper in the United Kingdom, titled "Fatties cause global warming", claimed overweight people were harming the environment because they ate more food and used cars and air-conditioning more, which caused more pollution.
"I thought this was a good example of how obese people are demonised."
Prof Stainton Rogers said she challenged the way many psychologists regarded obese people.
When overweight people did not comply with treatment or took risks with their health, they were often regarded as "stupid, feckless and lazy", and no acknowledgement was given to the barriers which held them back or alternative explanations of why they acted as they did.
Her research and theoretical work explores this situation, why the preconceptions operate and what is at stake for the people who promote the stereotypes and those who are subjected to them.
Her beliefs in this area led her to be recruited to work on the National Institute for Health and Clinical Excellence development group in the United Kingdom, which makes recommendations on projects and interventions around health-related behaviour change at individual, community and population levels.
Prof Stainton Rogers will today give a public lecture titled "Fatties cause global warming - disciplining bodies and governing souls", which will take a critical look at the implications for public health funding and activity, and at the real costs New Zealanders may be paying in terms of promoting prejudice, wasting resources and undermining wellbeing for the large number of people considered obese.
She will also encourage people to make small changes to make their lives healthier - like taking the stairs instead of the lift, or walking to work instead of driving.
"Those changes are easy to maintain and they make an enormous difference to your health."
Today's lecture will be at 5.30pm in the University of Otago Archway 3 lecture theatre.
