NEW YORK (CNN/Money) - The new "Tommy Girl" is coming to a store near you, but she isn't the stick-skinny, blonde, blue-eyed 20-something playing volleyball on the beach in her new red, white and blue "barely-there" bikini.

This young lady has gained a few pounds, and a few sizes.

With the recent barrage of statistics about the increasing average weight of Americans, retailers and, even more recently, designers like Tommy Hilfiger have begun adding larger sizes to their lines in an effort to capitalize on a market need. Research shows that about 33 percent of women are size 16, generally the biggest regular size sold, or larger, and analysts suggest companies are moving in a direction where they see a market becoming mainstream.

"It's a huge market -- it's an ignored market for the well-endowed," said Kurt Barnard, president of Barnard's Retail Consulting. "About 10 to 15 years ago, a lot of retailers wouldn't have dreamed about putting plus sizes into their stores."

The market for plus sizes is growing at a rate of about 10 percent a year compared with about 3 percent a year for regular sizes, said Margaret Whitfield, an analyst at Brean Murray & Co.

According to a Harris Poll released in March, about 80 percent of U.S. adults over the age of 25 are overweight, defined as having body mass index greater than 25. The figure has risen from 71 percent in 1995, 64 percent in 1990 and 58 percent in 1983. Body mass index (BMI) is a national guideline computed through a combination of weight and height. More than 50 percent of American women are overweight, according to the National Institutes of Health.

The jump to cash in on this market began with basic clothing retailers like Hingham, Mass.-based Talbot's and Charming Shoppes of Bensalem, Pa., adding sizes -- and even stores -- to accommodate their customers. But in tough times, even some designers have made the move to include larger sizes in an effort to increase their customer bases.

Last fall, Tommy Hilfiger (TOM: down $0.12 to $15.38, Research, Estimates) added bigger sizes to its clothing line -- welcoming new customers who like the designer's trendy styles but weren't able to fit into them previously. Already this year, Liz Claiborne (LIZ: up $0.22 to $31.15, Research, Estimates) added its "Woman" line of larger sizes to attract new buyers to its customer base, and Lands' End (LE: Research, Estimates) recently began plugging its women's collection through its catalog and Web site.

"Research showed a real need for clothing that was high quality and the same look for plus sizes," said Betsy Thompson, a spokeswoman for Talbot's. "It made a lot of natural sense for us to extend to women's sizes and women's petites."

Tommy Hilfiger's "Woman" collection intends to mirror the firm's regular-size fashions in style and design, but ranges from sizes 14 to 22. Clothes in the line include the designer's trendy bootleg and carpenter jeans as well as logo T-shirts, polos and oxfords.

Research and demand for "stylish, classic, All-American options in the plus-size market" drove the designer to expand its line, the company said.

As with Tommy's bigger sizes, many new plus-size lines offer styles similar to those available in its regular sizes -- and at comparable prices. While Hilfiger doesn't offer the same exact $59 jeans in a plus size on its Web site, it has a similar style in larger sizes costing $64.

Also trying to get in the game are clothiers aimed at the teen and pre-teen market. Hot Topic (HOTT: up $0.98 to $28.20, Research, Estimates) bolstered its offerings by adding its "Torrid" line -- sizes for girls who aren't as petite as some of their counterparts.

The retailer, based in City of Industry, Calif., launched nine Torrid stores across the country last year and into the beginning of 2001, and plans to open 12 more by the end of the year.

"The idea really came about from [the thinking] here's a niche, a segment of the market no one is looking at," said Tom Rail, Torrid's senior vice president and general manager. "We're responding to our customers."

Liz Claiborne plus-size swimsuit

Torrid's clothes range from size 14 to 26 and target teens and young women who want younger-looking, trendier clothes. Many of the company's customers previously opted to buy men's jeans and T-shirts rather than traditional plus-size styles, but now they can get the low-wasted jeans and belly-button-shirts of their slimmer peers.

While none of the retailers would reveal how profitable their plus-size ventures have been to date, all said they are pleased with the results so far.

"We're on target with Torrid -- we're on target with margin and profit targets," Rail said. " We have a very well thought out, well planned strategy and it's just working out great."

While Torrid is the only chain to solely offer trendy plus-sizes to young women, according to Rail, he said that more and more companies are inquiring about the lines they carry -- and considering adding to their own.

"All of the major department stores are in talking to these people. What they are going to do remains to be seen, " he said. "There are people who understand that the market is changing and you are going to see more and more people trying to get into it."

The more traditional women's clothiers like Talbot's (TLB: up $0.40 to $38.27, Research, Estimates) and Charming Shoppes (CHRS: up $0.04 to $7.95, Research, Estimates), which ventured into the plus-size game early, show no signs of letting up on the market anytime soon. Charming Shoppes bought large-size clothier Lane Bryant from Limited Inc. (LTD: up $0.16 to $20.92, Research, Estimates) in 2001 to grow its market share, and Talbot's aims to expand its 42 stores geared toward larger women to 150 by the end of 2005.