Although food bloggers sometimes snipe about her recipes being as low in nutritional value as they are in calories, Matthew Shear, St. Martin's executive vice president, says she "speaks to an audience that loves to eat and is looking for a way to eat the things they love at a fraction of the calories."
That audience, he adds, includes himself. He professes to be a big fan of her Lord of the Onion Rings recipe (155 calories) and her various mug cake desserts (you microwave them in a mug).
Dawn Jackson Blatner, a registered dietitian who has published her own cookbooks, calls Lillien's recipes low-calorie junk food.
But, Blatner quickly adds, that's not necessarily a bad thing.
"Two out of three people in this country are overweight. Do they need fewer calories? Is her whole enterprise teaching ways to achieve that? Yes," says Blatner from her Chicago office. For people who won't give up pizza and cheeseburgers, the Hungry Girl diet might not be a bad alternative.
Even Blatner says she's sampled some of Lillien's recipes, although she stays away from ones that use processed food products, preferring fresh fruit and vegetables.
"The spaghetti squash and butternut squash, the fun things she does with apples, I get most excited about those," she said.
Lillien believes her lack of credentials as a dietitian or a nutritionist actually gives her more credibility with her audience, which realizes she's one of them, just another foodie who doesn't want to sacrifice taste for trimness.
"If I'm helping people turn boxes around and turn cans around and read labels and understand what it means and learn how to maintain a healthier weight, then I'm doing good work," she says.