No doubt you've heard of the Freshman 15--the extra pounds first-year college students pack on that can be attributed to everything from stress-related eating binges to irregular-hour munchies to vending machine diets. The same could be said about workaholic entrepreneurs. (Eaterpreneurs?) "They often eat out, their calories are out of control, and the unpredictability of their schedules means little time for exercise," says nutritionist Julie Upton. "This can add up to easily gaining 10 to 20 pounds over a year."

It happened to Joie Rucker, who created a hip women's clothing line, Joie, in 2001. "I was working up to 16 hours a day and weekends," she recalls. "I ate junk food and stopped working out. One day, I couldn't fit into the sample size."

Nutritional consultant Oz Garcia, whose clients include CEOs familiar with the soft belly of hard start-ups, cites stress as a leading culprit, resulting in lack of sleep. "Not getting enough sleep affects cortisol levels," says Garcia. Over time, the more cortisol--a hormone produced by the adrenal gland--the more likely weight gain will occur, particularly in the abdominal area. Coping strategies only compound the problem. Relying on a venti latte to keep you going? You're wreaking havoc on your blood sugar level and setting yourself up to crash, burn, and overeat (try non- or low-fat yogurt with fruit or a protein-rich energy bar instead, Upton suggests). Swilling a Stella to decompress? Hello, empty calories (take a walk to unwind). Tip the scales in your favor by managing your weight--and stress--as you would your company: Make it a priority. Rucker got a personal trainer and went on the low-carbohydrate Zone diet, losing in one month the 15 pounds she had gained her first year as an entrepreneur.

Garcia advises having a masseuse come to the office or sitting in a sauna if you're too tired to work out. A stress-busting 45-minute session releases the same amount of endorphins as running for an hour, he says.

"There will always be 800 million things to do when you run your own company," says the L.A.-based Rucker. "Taking an hour for yourself won't change that. But working out and eating healthy will clear your mind, give you energy, make you more effective, and help you deal better with stress."