But as CBS News Susan McGinnis found out, there are also profits to be had from catering to plus-size people, whether or not they plan to trim down.
Dieting never worked for Nancy Summer, so years ago she decided to learn to like herself just as she is.
Summer says, "That was a really big change in my thinking. That maybe I was OK and maybe I should find things that were adequate for me or that I could use to make my life easier."
The only problem was, many regularly sized things didn't work for her.
She says, "I discovered that in the shower, I was having trouble reaching every part of my body."
So she turned to her friend Bill Fabrey.
He says, "I am an engineer by training, so I had this we-can-fix-anything attitude."
"The ample sponge," exclaims Summer. "Pretty soon, all of my larger friends wanted them and we said, 'Wait a minute, we can't keep giving them away.'"
Fifteen years later, that ample sponge is part of a very profitable mail order and online business called Amplestuff.
Showing a clothes' hanger, Fabrey notes, "You know larger garments, especially coats, weigh a lot more."
Amplestuff offers products and services for ample-sized individuals, everything from no-bend cleaning tools like "The world's longest tub scrubber" Summer says to extra -arge hospital gowns.
Fabrey says, "There are hospitals that perform surgeries on fat people that don't have gowns to fit them so we sell these gowns."
And it's no wonder ample stuff is doing ample business these days: its target market is growing fast.
In 2001, more than 44 million American adults were classified as obese, a 74 percent increase from 1991, according to the Centers for Disease Control.
And according to marketing analyst Gary Epstein, for companies catering to this group, the bigger numbers can mean bigger bottom lines. He is the CEO of Euro RSCG Tatham Partners.
He says, "You're looking at a couple hundred million dollars at least in money to the economy to solve the needs of people who may be battling this issue."
And that's not lost on companies like Charming Shoppes, owner of Lane Bryant. With an estimated half of all women now wearing a size 14 or larger, it saw an opportunity and just launched a new plus-sized magazine.
There are, of course, many businesses aimed at helping the obese get healthier regardless of their weight, like the Kelly Bliss line of workout videotapes.
But more and more companies realize there's money to be made with products and services to make large people's lives easier, whether or not they're trying to lose the weight.
Freedom Paradise near Cancun Mexico calls itself the first "size friendly resort," offering beautiful views, big chairs and a place to feel comfortable, no matter your size.
For comfort on the home front, the list keeps growing:
Carmakers like Ford have redesigned some interiors. Steelcase makes office furniture for larger workers. A couch found on fatcities.com has eight legs instead of four. Simmons offers a reinforced "Olympic" queen mattress, which is six-inches wider than the queen sized mattress developed for the average American in the 1950s. And casket companies like Batesville are even selling extra-size coffins.
Laughing, Summer says, "I am not sure I am thrilled about the large-size caskets, but who is?" But the extra attention, and the extra products, fit Summer's world just right.
She says, "That is kind of our motto, make the world fit you and try to live your life now and enjoy it. There is no reason that you have to suffer just because you are larger. They can lose weight later if they want to, but they can have a good time right now."