By day, they work at improving the health of the nation. By night, they face the realities of home life: two-career households, long commutes, homework, picky eaters and a shrinking amount of time to work out.

So how do health professionals balance their expert knowledge with their lives?

That's the question that the Lean Plate Club put to four prominent women in the world of nutrition and public health: Alice Lichtenstein, professor of nutrition at the Jean Mayer-USDA Human Nutrition Research Center at Tufts University; Bonnie Liebman, director of nutrition for the District-based Center for Science in the Public Interest; Lori Mosca, director of preventive cardiology at New York Presbyterian Hospital and medical adviser to the Washington-based Sister-to-Sister Foundation; and Susan Yanovski, director of the Obesity and Eating Disorders Program at the National Institute of Diabetes, Digestive and Kidney Diseases.

Here's what they not only advise, but do:

Make family time active. Lichtenstein joined a gym with her teenage daughter, which they use together on weekends. Her family also takes long walks on Saturdays and Sundays, "regardless of the weather," she said. Mosca and her husband, a cardiac surgeon, use their limited recreation hours to bike and jog with their sons, ages 12 and 14. The family shares a love of swimming and has made a local pool a frequent family social setting. "The family that plays together, stays together," said Mosca, who often prescribes 30-minute family walks for her patients.

Find a technical edge. Yanovski uses TV Allowance (www.tvallowance.com), a $99 timer ($79 each for additional units) that plugs into the television or computer. Parents set an allowance of screen time. The device is password-protected so that each family member can have their own account. When the time is up, the television or computer turns off. Yanovski's kids can earn more television or computer time by spending time on the family's treadmill: a 30-minute workout gets 60 minutes of screen time.Plan ahead. Lichtenstein stocks frozen chicken breasts, veggie burgers and shrimp. She buys large pieces of fresh salmon at Costco and freezes individual portions. "I have also found the joys of frozen vegetables," she said. White and brown rice, couscous, cereal and plenty of pasta are pantry staples. She shops weekly for fresh produce, including multiple heads of lettuce. To help the lettuce last longer, she uses the outer leaves of each head first, rather than using up one head at a time.

Pick your battles. Liebman knows it's easy to get her kids to eat whole grain cereals and bread. "But whole-grain pasta, pizza dough and brown rice are tough," she said. So she doesn't push them. She also lets her kids have up to one junk food item per meal. "I would rather they have none," she said, "but I don't want it to become a forbidden fruit."

Yanovski tries "to go where the money is, where it's easy to cut things out." So the family drinks nonfat milk, water and no-calorie beverages between meals. They also eat carryout and convenience foods, including bags of pre-mixed salad, cut up vegetables and roasted chicken from the supermarket. Yanovski's main focus is on helping her family to be more active. "It's hard to get your kids to want to eat broccoli and spinach, but it's easy to reduce sedentary behavior," she said.

Add healthy fat. Which ones? Lichtenstein said that the research is still unclear, so she hedges her bets by buying bottles of soybean and canola oil and rotating between the two. For salads and specialty dishes, she uses olive or sesame oil. About five years ago, Lichtenstein noticed her kids were passing on salads. So she added back regular salad dressing, which helped boost salad consumption. Another trick: Lichtenstein uses an assembly line for salads. She prepares the lettuce, but lets each family member add the salad toppings they like best.

Lookout for yourself. Liebman joined a gym near her house. She can spare only 20 to 30 minutes for a workout. "It's a very short window, but I really feel better," she said.

Lichtenstein gets to the office at 6 a.m., when she is most efficient, and leaves by 5 p.m. She also brings a lunch daily to save time and ensure healthy eating. Throughout the day, she takes the stairs to add more physical activity.

Mosca builds in a few minutes of solitude every day to recharge. "It's critical to not feeling overwhelmed in today's society," she said.

Involve the clan. Cooking is a family activity at Mosca's home. Her husband shops for ingredients. Mosca and her two sons do the cooking. "I cook most of my food for the week on Sunday mornings," she said. "If you wait to cook until after a hard day of work, you have to overcome the impulse to order out for pizza," she said. Plus the family tradition means that Mosca's two sons now also know how to cook for themselves.

Make your food fast. "Let the supermarket do some of the cooking for you," Liebman said. She keeps low-fat frozen spinach-and-cheese ravioli from Costco in the freezer ready to be dropped into boiling water. "It doesn't get any better than that," she said. Boboli pizza rounds can be topped with reduced fat mozzarella cheese, sliced artichoke hearts, onions and mushrooms for another main course. And fresh tortillas from the dairy case are topped with tomato-and-black-bean salsa from Trader Joe's, sprinkled with low fat shredded cheese and microwaved for a quick entree.

Encourage snacking. Just make it healthy. Yanovski buys pre-packaged 100 calorie snacks, recently introduced by Nabisco. Among the choices: Teddy Grahams, Wheat Thins, Triscuits, Chips Ahoy, Oreos, Ritz crackers and Barnum's Animal crackers. Liebman addresses the raging hunger experienced by most kids between school and dinner to offer fruit and vegetables for snacks. One day, it's cantaloupe. The next apples, grapes, pears or baby carrots and slices of fresh sweet pepper with ranch dressing. "The minute I walk in the door, which is not long before dinner, I cut up fruit and give it to my kids," said Liebman. "Find me a kid who doesn't like watermelon or bananas."

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