British researchers have found that men who are in stressful situations rate larger sized women as more attractive.
The researchers from Newcastle University put 41 men in high-stress situations then measured how they judge potential partners.
When compared with a control group of 40 men who were not stressed, the researchers concluded that stressed men were more likely to go for women with a higher BMI.
"There's a lot of literature suggesting that our BMI [body mass index] preferences are hard-wired, but that's probably not true," co-author Dr Martin Tovee told BBC News.
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Dr Tovee and his colleagues undertook the research to investigate whether cross-cultural preferences for body size were linked to stress.
"If you look at environments where food is scarce, people's preferences for body size in a potential partner are shifted. [The preference] appears to be much heavier compared to environments where there's plenty of food and a much more relaxed atmosphere," he explained.
"If you're living a far more stressful, subsistence lifestyle, you're going to have higher stress levels."
To create stress, the participants were put in interview and public speaking scenarios. The researchers noted that the change in stress levels made them more attracted to a wider range of body sizes, particularly larger women.
"These changes are comparatively minor in comparison to those you get between different [cross-cultural] environments. But they suggest certain factors which might combine with others and cause this shift," Dr Tovee said.
"If you follow people moving from low-resource areas to higher resource-areas, you find their preferences shift over the course of about 18 months. In evolutionary psychology terms, you try to fit your preferences to what works best in a particular environment."
Dr Tovee said this research shows that what is perceived by society as the "ideal" body shape could change if environmental conditions were altered.
"There's a continual pushing down of the ideal, but this preference is flexible. Changing the media, changing your lifestyle, all these things can change what you think is the ideal body size," he said.
Dr Simon Crisp, a clinical psychologist at Monash University, told ninemsn that the research is not surprising.
"Stress changes our mental state, it changes our brain chemistry, but it also changes the way we process information so the things we look for in a stressed state might be different to when we're not in a stressed state," he said.
Dr Crisp said individuals should acknowledge that external factors can influence who they are attracted to.
"In my clinical work I see people who talk about how they started relationships and often it's things that were going on for both of the parties that were quite influential as to why they chose to start the relationship," he said.
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"Being a bit more self-aware of those things can perhaps help us make better and more lasting and more positive long term decisions about who to form relationships with."
The research was published in the journal Plos One.