When you look at Siren on American Gladiators, besides the costume and the intimidating look, you're sure to notice the sculpted muscles.

Valerie Waugaman sees fat.

''The camera really does add 10 pounds,'' says Waugaman, the 29-year-old Cleveland resident who plays Siren on the NBC series. But she is not some timid little birdie who thinks of anorexia as a means to a better career. In fact, she is very fitness-conscious.

Her personal eating habits include lots of vegetable and protein supplements. So much so that when confronted with the catering table while American Gladiators was taping in November and December, she knew she was going to put on weight.

In her professional life, the graduate of Brecksville High School and Ohio University admits that even the slight bulking up that occurred with Gladiators can be a problem. ''I have sort of a skewed perspective,'' she said in a recent telephone interview.

After all, Waugaman is also a professional bodybuilder with IFBB, or International Federation of Body Building and Fitness. Competing in the figure category, she has won several events and is in training for Columbus' Arnold Sports Festival (yes, that refers to Arnold Schwarzenegger).

Waugaman came to bodybuilding as a way to promote Octane Cafe, a health-conscious restaurant on Cleveland's Euclid Avenue, where she is co-owner and marketing director. Her fiance, Sam Eells, founded the restaurant and hopes to turn it into a national franchise.

So Waugaman constantly preaches the gospel of physical fitness and healthy habits. In addition to boosting the restaurant, she hopes her appearances on American Gladiators will be a springboard to a larger role promoting her ideas, especially to young people.

As a young person, Waugaman was athletic, she said, and ''I was lucky to have good genetics. . . . I was healthier than most, but I ate a lot of frozen dinners, cheese and bologna and things that were really not healthy.''

These days, she said, ''I wouldn't say I'm a vegetarian, but most of my diet consists of vegetables. . . . Lots of spinach. . . . And lots of fish, tofu, natural protein power in shakes.''

That, and a lot of training, not only helped her in bodybuilding but in feeling good overall. ''My skin is better,'' she said. ''My hair is better.'' And when American Gladiators was starting, she was already known well enough in the bodybuilding world that — thanks to a referral from Flex magazine — the show came to her.

Not that it's all been easy. Even in training camp, she said, there was a lot of competition. ''You want to stand out,'' she said. ''That's the nature of who we are. We want to give 100 percent effort. But at the end, we're shaking hands.''

And people really do get hurt on the show. One of the nonprofessional contenders was eliminated by an injury on the first telecast. Waugaman has been sandwiching interviews in between visits to the Cleveland Clinic for physical therapy. While she is glad to have a chance to compete in athletic events beyond the posing of bodybuilding, she said it has been ''emotionally and physically exhausting.''

''You're putting your body through a lot of stuff,'' she said. Even contestants who look easy to beat can surprise. ''No matter what their size is, they can have power and they can have heart.''

There were other issues to consider, too, such as her on-show name. She did not get to pick it but said ''the names are a reflection of who we are.'' She did have some input about her costume, and made sure that it was something she could work in comfortably.

And the show — its regular time slot is 8 p.m. Monday — seems to be working. To be sure, the competition is less intense because the writers strike has taken a lot of hit shows off the air. But NBC has been pleased with the early numbers, and it will replay an episode at 10 tonight to make up for the strike-caused loss of a full Golden Globe Awards telecast.

So it appears likely that Waugaman will be putting on the Siren suit again. And that may take her out of bodybuilding. She admitted that it's not good to go back and forth between her figure-competition regimen and American Gladiators, so ''I'm going to have to make some choices.''