I was an acned, bespectacled little girl," says Claudia Wilbourn. "I had a lot of adolescent scars." Not any more. Just as that 97-pound weakling in the Charles Atlas ads of yore was transformed, Wilbourn, 29, a sculptor from San Juan Capistrano, Calif., today has become one of the nation's top female body builders. Among the others: Lisa Lyon, 27, a cum laude UCLA graduate and the current World Women's Body Building Champion, and Stacey Bentley, 23, winner of several recent national titles. All three women are Californians who devote most of their waking hours to their sport, and they realize others have neither that much time nor interest. Still, the training that goes into body building, they insist, can benefit most women.

Muscle. Contrary to the image of male body builders, women in the sport don't necessarily get muscle-bound. That's because they have low levels of the male hormone testosterone, which leads to bulking of muscles. Though some women are rumored to use steroids to make up for the testosterone, Wilbourn says, "A normal exercise program will not lead to muscularity," and adds, "You can control it. Your body is not going to become bizarre or weird. You may not get any larger at all, just shapelier. I walk down the street, and nobody knows I'm a body builder. When you relax, it doesn't show."

Sex. All three agree that body building, like any other strenuous exercise, leads to an overall sense of physical well-being. "It definitely makes you more sensual," says Lyon, the most publicized woman body builder. "It increases your awareness of, and the blood flow to, all parts of your body. Your sexual endurance is better. And so is your sense of yourself." Adds Wilbourn: "You radiate sexuality. It's like taking uppers—you get a rush." For Bentley, who moved from Pittsburgh two years ago, the reaction of men to her new body has ranged from curiosity to unabashed approval. "I get letters from a lot of men," she says. "They say I look terrific and they wish their girl friends or wives looked the way I do."

Diet. Essential to any workout program is a sound diet. Bentley, who was 32 pounds heavier when she started weight lifting, even insists, "Diet comes first." All three women emphasize a low-fat, low-carbohydrate diet with menus that include chicken or fish, fresh fruit, salads and vegetables and, in Bentley's words, "lots of vitamins." For breakfast, Lyon regularly eats 50 vitamin and mineral pills as well as a big dish of chopped green apples, lecithin, grains and acidophilis milk. Wilbourn warns, "If you diet but don't exercise, you'll look flabby." Because she is hypoglycemic, she eats small meals all day long and avoids such foods as red meat, cheese, nuts and most dairy products. Lyon, who eats only twice a day, feels eggs and cheese are a good source of protein. "There is no magic diet," she says. "Your body knows what it wants. People who look for secrets deny their own intelligence."

Training. Though all three work out with weights every day, they recommend caution for the beginner. "I've been training for 10 years," says Wilbourn. "I didn't just jump in and exercise seven days a week. I would have burned out right away." Lyon agrees: "You need advice or you can hurt yourself," and suggests, "You should probably start on just one part of your body." Wilbourn recommends that beginners look for a qualified trainer—and ask questions if they are not sure of his or her background. As for weight lifting, Lyon has a rule of thumb. "To gain inches," she says, "you should use heavier weights and few repetitions. To lose inches, use lighter weights and repeat often." Lyon also stresses the need for aerobic exercise to go along with weight training, such as running, swimming, yoga or dance on alternate days.

Mental Outlook. The hidden benefit of body building for women may well be a dramatic change in attitude about life in general. "It meets a lot of needs," says Wilbourn, "and not just physically, but emotionally and intellectually, too. I'm not an athlete. In fact, sports bore me to death. It's the motivation that interests me. I'm sculpting my body." All three women report that they organize their time better and their attitudes are more positive. "When you are more confident about how you look," says Lyon, "you feel better. You don't have to act out a passive female role. If you've only got so much time to spend on fitness, why not spend it in the gym?"