Super-sized media? More overweight actors in TV ads

>>> we hear about it every day, america is getting bigger and we're seeing it reflected in all kinds of ways, overweight and obese people featured in more tv ads. it's a trend that made the front page of " usa today " as more big names are used to warn this growing nation. here is michelle franzen .

>> reporter: it is a new trend in advertising, super sized commercials showing overweight people in ads selling everything from running shoes to what looks like an ad for fast food .

>> my dad eats five buckets of fried chicken .

>> reporter: a closer look at this commercial --

>> my dad can eat a quadruple l burger --

>> reporter: reveals a bigger message from blue cross / blue shield .

>> one day i'll be able to eat twice that.

>> reporter: advertising experts say it is a reflect shup of the times when two-thirds of americans are considered overweight or obese.

>> i think we're reaching a point where what bloomberg is doing in new york, michelle obama 's let's move campaign, advertisers recognizing they have to use their power to help change behavior and encourage positive habits.

>> reporter: nutrition experts say just like in real life a push for change can backfire if companies cross the line.

>> what doesn't work when it comes to behavior change is shame and blame. everyone walking around with enough guilt and when it comes to body image and when it comes to weight.

>> reporter: a point that made headlines this past week when a tv anchor fought back against a viewer's comments criticizing her weight.

>> the truth is, i am overweight.

>> reporter: people have taken to the internet to express their support or distaste of recent ads including nike's commercial saying it exploited nathan's weight, but he said the backlash won't stop him.

>> that just motivates me more.

>> reporter: larger than life issues front and center in a whole new way. for "today," michelle franzen , nbc news, new york.