"My favorite dessert is chocolate pudding pie with Cool Whip™," said 28-year-old fitness professional John Damon. "I just love it." Apparently it is possible to stay in shape and eat what you want.

For those with bad memories of high school physical education classes, a career as a fitness pro can conjure up nightmares of ill-fitting exercise clothing, running until you drop, or a ban on favorite treats. But in fact, a personal trainer needs less rigid discipline and more scientific knowledge coupled with financial acumen. "If you want to be good at this, you need an appreciation for both health and financial issues," Damon said.

A typical day begins early in the morning when Damon opens the Mount Auburn Club in Watertown, Mass, where he is co-head. For the next 13 hours, he educates new members on safe equipment use, does fitness assessments, attends meetings, leads group exercise classes, and has a number of personal training appointments with members who have hired him. The more clients he has, the more he earns, with 60 percent of the hourly fee going to him and the rest to the gym.

When Damon is free in the late evening, he sometimes trains with his own coach. But even if he goes to the movies, he thinks like a fitness expert. "You can never get away from this business," he said. "I've been known to rate the movies I see according to the fitness level of the stars."

Mother inspired athletic son
Fitness begins at home, and Damon credits his mother with starting him on an athletic career that includes high school state records in several sports and a full scholarship to play Division I football. "I learned how to play baseball from my mom. She was such a good athlete that when she played in the mother-son baseball game, the mothers won."

When family circumstances made it impossible for him to play college football all four years, Damon knew he could never play professionally. Since he majored in finance, he settled on a career in financial services, only to discover he disliked the work. When he realized he didn't mind getting up for 6am appointments to train private clients, but resisted office meetings at 7am, he decided to change jobs.

Weight and see
Working with individual clients is the aspect of his career Damon finds most rewarding. "People tend to come to me because they want to feel good, reach a sports goal-or simply look better naked," Damon said.

An insistent spouse or partner is sometimes the most powerful motivator of all.

However lofty the goal, Damon reminds exercisers that fitness takes time and properly-applied effort based on principles of biomechanics and physiology. Dealing with clients who expect overnight perfection frustrates him more than any other aspect of his work, he said. "You don't get instant results. Period," he said.

But hope springs eternal, and January is the busiest month of the year courtesy of New Year's Resolutions.

It can be exhausting summoning up the focus required to coach individuals and run programs. Damon said potential fitness gurus need limitless enthusiasm, energy, and listening skills as well as professional credentials. It makes weight-lifting and stomach crunches seem easy.

Still, such multitalented people can expect to be paid well. Midcareer fitness professionals earn between $60,000 and $70,000, while top trainers can earn over $200,000. Add film and TV work or a fitness video, and the numbers go much higher.

So, what is Damon's advice for those looking to get in shape? "I tell my clients that the habits you need for success in the gym are the same habits you need for success in life: attendance, effort, and proper form. If you can do that, you are going to reach the goal you set."

- Ruth Morss, Salary.com Contributor