If advertisers are to be believed, the perfect man has tree-trunk legs, abs that double as a bomb vest and a shoe size that exceeds his percentage of body fat.

But for all that flawlessness, a new study finds male consumers are equally responsive to ads featuring ordinary-looking guys. And given the choice between an Adonis and no model at all, men rate the latter ads as more effective.

The research, which appears in the journal Body Image, supports arguments that idealized physiques aren't needed to make an ad successful, and may in fact cause diminished response among consumers.

"They can much better relate to everyday guys because it's easier to imagine themselves using that product," explains study co-author Phillippa Diedrichs, research fellow at England's Centre for Appearance Research. "But at the moment, ads are so dominated by muscular images that people don't actually have the opportunity to vote with their wallets."

Researchers from American University report that Playgirl centrefolds lost 5.4 kilograms of fat and gained about 12 kilograms of muscle between 1973 and 1997.

Similarly, a study in the International Journal of Eating Disorders finds boys' action toys such as G.I. Joe have, over a 30-year period, come to boast muscularity not seen in "even the largest human bodybuilders."

This cultural bias is in direct conflict with research that shows women typically desire male bodies that have nine to 14 fewer kilos of muscle than most guys think — a conclusion that appears to be supported by Diedrichs' study.

In experiments with more than 600 men and women, aged 17 to 25, participants rated ads featuring average-sized male models as being equally effective as those depicting muscular models (the study controlled for facial attractiveness and expression). This evaluation was consistent across both genders.

Furthermore, the male participants considered ads featuring no model at all to pack a bigger commercial punch than those featuring models that looked as though they could open a beer bottle with their pecs.

Diedrichs suggests stereotypes linked to good grooming may be a contributing factor. In a previous U.K. study, she says, young men confronted with images of male muscularity perceived the models to be vain — "a trait which is commonly perceived to be feminine or homosexual."

Michael Kaufman, a gender-issues educator from Toronto, believes the new findings are largely the result of heightened media literacy. A recent 1,000-person survey for Dove found 80 per cent of Canadian males feel ads stereotype their gender.

"Men are benefiting from 20 (or) 30 years of discussion among women about all these issues of body image and depiction in advertising," says Kaufman. "They know most men don't look like (professional models). And the fact they can joke about it, and distance themselves, means that those types of ads are going to have less impact."

When it comes to images that sell products, however, a Canadian marketing expert says the issue is complicated by everything from consumer age to the body types in vogue at a given time.

"We all know that we're supposed to say: 'Oh, it's terrible they use all these attractive people; they should show regular people. Blah, blah, blah,'" says Barbara J. Phillips, a professor at the University of Saskatchewan. "But the truth is that we're very poor at judging how effective an ad is on ourselves.

"You have to remember that advertisers aren't trying to oppress anyone. If they knew for sure that regular men were the best way to sell products, you would only see regular men."

YouTube: Old Spice commercial