As a working mother of two, Lisa Hark knows what it’s like to have hungry kids in the car at the end of a long day, begging to stop at the Wawa for a donut. “Healthy food first,”is Hark’s mantra, and she’s often found that once the hunger pangs have been satisfied, the siren song of junk food fades off into the distance.

Hark’s expertise doesn’t just come from personal experience, though. As director of the nutrition education and prevention program in the School of Medicine, Hark has been advising doctors, patients and students on nutrition for more than 20 years. She’s also edited several books on the subject, including “Medical Nutrition and Disease: A Case-Based Approach,” which is used in medical schools around the world.

When DK Publishing approached her to co-write (with Darwin Deen) a new book called “Nutrition for Life: The no-fad no-nonsense approach to eating well and reaching your healthy weight,” they tapped both her expert knowledge and her practical smarts.

What they had in mind, says Hark, was a clear, comprehensive guide to nutrition to “clear up all the confusion.” With so many diets being marketed to the public, there’s a glut of information out there, she says. Now it’s time to make sense of it all. “The media latches onto fad diets and scares the public. Now people are afraid to eat carbs,” says Hark. “The thing about those diets [like the popular Atkins] is that everyone loses weight because they cut out food groups,” but the diets may be hard to maintain or unhealthy in the long run. In “Nutrition for Life” Hark and Deen take apart 45 of the most popular diets—from Herbalife to the Zone—and assess their pros and cons.

The book’s larger goal, says Hark, is to give readers, “a step by step guide to what to eat to feel better, look better, live longer and be healthy regardless of age and medical problems.”

To make the advice easy to digest, DK has followed the lively format that has made it a favorite among kids and grownup kids alike. Every spread in the 300-page book pops with photos, charts, menus, case studies, “jargon busters” and fast facts.

“People are more and more interested in learning about nutrition,” says Hark, who included sections on food for toddlers, school-age children, new mothers and athletes in the book as well as information on how food can help prevent or treat such diseases as diabetes and arthritis. The first step, says Hark, is to take a look at your current eating habits and medical history. Then, get ready to make some changes, not for a week, not for a month, but for life.

Lisa Hark will talk about “Nutrition for Life” at noon on Feb. 2 at Penn Bookstore. For more information, call 215-898-7595 or go to http://upenn.bkstore.com. For more on the book, visit www.nutritionforlifebooks.com.