Thin is still in for the advertising world, despite majority of female consumers showing resentment. New research on the subject shows that many women may personally resent thin or super-thin volunteers approaching them for promoting various products, but they do take the message seriously.

"It's a case of conveying an aspiration message," says Matina Covello, a strategy executive with a marketing communication company based in Dubai Media City.

The conclusive message is derived out of two such research conducted by Oreo cookies and Dove, in their recent "Campaign for Real Beauty". On the face of it, the survey conducted by cookie makers Oreo revealed that women who had just seen thin models were nearly four times more likely to turn down a snack pack of cookies offered as thanks for their participation than women who hadn't.

On similar grounds, college-going girls that participated in a research to study the impact of Dove's "Campaign for Real Beauty," shows that ads featuring thin models made women feel worse about themselves but better about the brands featured. The study was conducted at Villanova University and the College of New Jersey, in the US.

Seeing thin models also made college-age women turn down a snack pack of Oreo cookies offered as thanks for their participation in the study, or to opt for a reduced-fat version.

Women in a sample of 194 college students aged 18-24 expressed more negative feelings about their attractiveness, weight and physical condition after seeing thin models than before. So-called high self-monitoring women, or those more concerned about what others think of their appearance, were the most negatively affected by seeing the thin models in the study.

"At a personal level, all the participants, or for that matter women in general," explains Martina "may not be appreciative of the slim figure of promotional girls, but they clearly understand the message and it's in fact absorbed for long-term retention."

Communication experts are still collecting data and are in the process of collating a detailed research report, but initial indications in survey found that despite the negative effect on their body image, women preferred ads showing thin models and said they were more likely to buy products featured in those ads than in ones showing "regular-size models".

"The really interesting result we're seeing across multiple studies is that these thin models make women feel bad, but they like it," said Jeremy Kees, a business professor at Villanova about the study in a special paper on the subject. "They have higher evaluation of the brands. With the more regular-size models, they don't feel bad. Their body image doesn't change. But in terms of evaluations of the brands, those are actually lower."

Martina believes that this is a sensitive areas where advertisers cannot impose a thin image in the minds of consumers beyond a point, as "that may backfire in reality".

The findings create something of a quandary for marketers, who might have a positive effect on young women's self-esteem by showing more typical women in ads, but suffer in the marketplace as a result.

"I'd tend to be cautious about using models in advertising that wouldn't maximise the attitudes and evaluations of the advertising and the brands," said Kees in support of the rational. "Certainly [Dove] got a lot of publicity, and it's a great, innovative campaign. But in terms of the bottom line of how that might be impacting ... purchase behaviour, I'm not sure."

Kees said the professors landed on the Oreo tactic, in which study participants didn't know their post-ad-exposure cookie-eating would be monitored, as a way of studying real behavioural impact in addition to the usual survey responses regarding ads.

The Dove Self-Esteem Fund, backed by its Campaign for Real Beauty, has exceeded its original goal of reaching one million young girls by this year and expanded its target to five million by 2010 in the US.

The data shows a definite, if short-term, link between thin models in ads and eating behaviour, but Kees said he wasn't comfortable making the leap that seeing thin models could cause eating disorders.

"That's a far stretch to infer an eating disorder from a one-time choice," Kees said in response to a query fromAdAge, but added, "that's certainly a scenario that would be rich for future research."

The new study in part concurs with and in part diverges from some prior research on the impact of thin models. Research reported in 2005 and 2006 from psychology professors at University of Sussex and University of West England in the UK concluded that ads featuring ultra-thin models do make women feel worse about their looks, but aren't any better at selling products than ads featuring more typically proportioned women.

There has been an onslaught at government level against the phenomenon of using thin models with authorities and brands vowing to discourage being thin to the extent of being unhealthy.

France had earlier this year passed a law that would ban the use of ultra-thin models in ads, and authorities in Spain last year banned ultra-thin models from runways. Unilever also vowed to not use size-zero models in any of its advertising.

In a statement, a spokesman for Unilever said the company believes its approach works. "Unilever is confident in the effectiveness of its advertising," he said. "We believe women have the right to feel comfortable with their bodies and not suffer from lack of self-esteem brought on by images of excessive slimness."

Dove's campaign, he said, has "penetrated society and started a dialog about real beauty," adding "we are thrilled by the overwhelming positive responses we have received from women (and men) as a result of the campaign."

Despite those efforts, he said: "There is no question that women and young girls are being bombarded with unrealistic messages and images of beauty that impact their self-esteem." But, he said: "We are excited to see now (and have seen in the past couple of years) a growing trend towards more realistic and healthy looking women in advertising and in the media."