We all know girls and young women face incredible pressure to be thin, but experts are warning that today's college-age and 20-something females face a dangerous combination of pressures.

Not only are today's young women bombarded with "stick thin" images, but they're pressured to fit in on the party scene as well. Mixing the two stresses can lead to destructive behavior that every parent needs to know about.

It may sound harmless enough… swapping out a meal for a martini every once in a while. But experts say for many young women it's becoming a habit that's downright dangerous.

Dr. Douglas Bunnell is an eating disorders specialist.

"There's a tremendous weight consciousness out there. At the same time you have people drinking and sort of encouraged to drink," Bunnell explains.

Dr. Bunnell says he's treating more young women who are giving up food calories for alcohol. Although not an actual condition, some have dubbed it "drunkorexia."

"You know at the extreme, drunkorexia can lead to people being so badly nourished that their abilities to function cognitively and emotionally is impaired," Dr. Bunnell says.

Lynn Grefe with the National Eating Disorders Association is concerned too.

"The drunkorexic is really adding onto the problem of anorexia, and they truly need counseling before the problem goes too far," she warns.

It's an on-going struggle for many co-eds …according to "Piper." That's not her real name. The 21-year-old student, who admits she's had food issues for years, says things got much worse when she went away to school.

"I think it was more just, there was more social interaction with other people and I just, we were going out more so I had to watch what I was eating when I was going out," she says.

"Piper" says she and her friends counted calories to stay within a certain limit if they were going out on the town.

"Beer was like--you don't drink beer unless you like haven't eaten all day," she recalls.

Who engages in this behavior? While some of the young women are diagnosed anorexics, many others went to school normal, healthy eaters, but are panicking about those extra college pounds.

"My concern about the drunkorexia phenomenon is that it starts people on a pattern of disordered eating that can push them in the direction of a formal disorder," Dr. Bunnell says.

Another concern is malnutrition. "Piper" admits she's seen some pretty crazy justifications.

"I know some girls who, they'll replace some of their drinks with things they think are more nutritious, like Bloody Marys, 'cause it has like tomato juice in it. They think that can replace a meal," Piper explains.

Whether you're a co-ed or twenty something… how do you tell when there's a problem that needs to be addressed?

"If you are doing mental algebra to compensate or manage your drinking in response to your eating, simply that sign is worrisome," Dr. Bunnell warns.

"I would recommend that everybody encourage people to go for treatment. There's nothing to be ashamed of," Grefe adds.

Piper has changed schools, and with help from her family and counselors, she is on the way back to a healthy weight…and outlook.

She wants all parents to know the issue is a big deal.

"In college, if you struggle with the food and the drinking, that's your life, that's who you are rather than the school, that's kind of on the side," she says.

If you know someone who might be struggling with the issue of giving up food calories for alcohol, the National Eating Disorders Association can help.

You can call their helpline at 1-800-931-2237 or visit their Web site.

They can refer you to treatment options in your area.