Do I have to buy that extended warranty?

International research suggests losing weight may help people get a job - and their New Zealand counterparts say it can't be ruled out here, either.

It is often said that there is a "skinny privilege" that means that people who are heavier may be missing out on a range of opportunities, including pay rises and job offers, because of stigma.

But new research by economist Rebecca Diamond at Harvard University, using the example of women who have taken GLP-1 weight loss drugs, offers another insight.

In the working paper, published by the National Bureau of Economic Research, Diamond compared the marriage and employment rates of women on GLP-1 drugs to a control group of women who wanted to take the drugs but hadn't yet started. Women who were unemployed increased their likelihood of securing a job by 26.9 percentage points after a year-and-a-half of taking a GLP-1.

She said it was probably due to people's first impressions of those women.

Diamond said, if the rise in job rates were due to mood and productivity, women who were already employed before starting GLP-1s might also be reporting increased hours or promotions, but they were not.

"You might expect if you're just more motivated and more excited about taking on new things, you might have seen some increase in those metrics. But we don't see that," Harvard quoted Diamond as saying. "That's why I think it's more about the first impression margin."

Julie Trafford, associate professor for planetary health in the AUT school of science, said it could be assumed there were similar issues at play in New Zealand, although they would be complicated by New Zealand's different labour markets, demographics and potentially different cultural norms.

She said there had been research done in Pacific Island communities that suggested weight stigma or body shaming were a concern. "There have also been studies that suggest this could be more of a problem for women than perhaps men… I know as a woman, if you put a bit of weight on, especially around the middle, people can assume you're pregnant and assume all kinds of things that would not necessarily be the same for men. And also sometimes, you meet up with people in work and other places who say, 'oh, you're looking good. I think you've lost some weight.'"

She said some New Zealanders had been involved in trials of Wegovy and other weight loss drugs but there had not been sufficient time for the impacts of weight loss drugs to be seen at a population level.

"We don't quite know yet the longer term impacts and people haven't necessarily lost a lot of weight yet. But I am aware that some 18,000 people now have been prescribed Wegovy."

She said because it was not funded, there was probably an inequitable and uneven distribution of people who could access it, which would distort any data on employment opportunities as a result of the weight loss.

One woman, Lou, who recently lost a large amount of weight, said she had noticed she was treated differently in her workplace.

"In my experience, when I was bigger nobody really paid much attention to me. People would come into the office and barely say hello. But that changed when I was smaller.

"I'm not skinny now - but about a size 12 when before I was up to a size 20. I had clients stare at me when we had lunch meetings, one place I visited let me know where the nearest KFC was from their office. Like, quite cruel stuff.

"I'm a qualified personal trainer and worked on the gym floor when I was bigger too. I remember telling people that I had finally graduated from PT school and one of them responded 'what! you? how on earth are you working in fitness?'"

Professor Peter Shepherd, at the department of molecular science in the University of Auckland's faculty of medical and health sciences, said there would be an element of personal motivation and how people felt about themselves that affected what happened to them.

"Both physically and the prejudices and stigmas that come with it.

"I think if people see people making an effort to do anything, a lot of employers will give credit for that, as well. There's definitely a stigma in society about weight, I think it probably applies to men and women, that if you're able to lose weight it'll put the odds in your favour for many things.

"It definitely increases self-confidence. Self-confidence is a big part of that issue in Harvard [research], it's a big part of relationships… work or interpersonal relationships. Confidence in a job interview or something is often the thing that tips you over the line."

He said people who were spending more on weight loss drugs could also be spending less on alcohol or food. "We don't hear about the savings that people will make in their lives and those savings can be quite a lot of money. Weight loss drugs are going to keep reducing in price over time so it won't be far in the future before the benefits outweigh the cost... It's just a total revolution."