Despite the demand for recent diet books, some dietitians have expressed doubts about the effectiveness of some newly published weight-loss plans.

One such book, the New York Times bestseller “Sugar Busters,” plays on the principal that high levels of insulin slow the breakdown of fat. The “Sugar Busters” plan, similar to diet books “The Zone” and “The Five Day Miracle Diet,” suggests dieters cut sugars from their diets.

“Unfortunately, that’s not how it works,” said Heidi Petersen, registered dietitian at the Iowa State Wellness Center. “There are a lot of fad diets out there, [but] I wouldn’t recommend them.

“They’re not necessarily safe as far as appropriate weight loss,” she said. “[People need to] be sticking to the food guide pyramid.”

According to the book’s Web site, “Sugar Busters” can help you lose weight, lower cholesterol, achieve optimum wellness, increase energy and treat diabetes. Among the high-starch foods the book recommends dieters avoid are pasta, white rice, white bread, potatoes, carrots and corn.

“It sounds really scientific, but they’ve taken it to an extreme,” Petersen said. “If you’re cutting out a lot of these foods, you’re going to be cutting out a lot of essential nutrients.”

However, some say the sugar-free diet will work, at least to some extent.

“The diet will work in the short-run because in effect it is a lower calorie diet,” said Elisabeth Schafer, professor of food science and human nutrition. “Any diet works because it changes your normal eating habits, but there are serious questions about the effect in the long-run.”

Schafer said one of the reasons the diet may not work over a long period of time is because it does not incorporate long-term changes.

“It doesn’t take into effect physical activity,” she said. “[People] get back into the old habits and the weight comes back.”

Petersen agreed that more than simply avoiding sugar needs to be done to lose weight.

“[The diet is] not a lifestyle change,” Petersen said. “They may be able to follow it for a couple of weeks and lose a few pounds, but they may be experiencing water and muscle loss. They’re probably not losing [weight] from the areas they want.”

Petersen said she has been repeatedly asked about the successfulness of diet plans featured in books.

“People want to know if they work, but unfortunately … we look for easy answers,” she said.

Weight-watchers looking for a successful diet should try to determine if the diet is a fad and if it is a money-making ploy, Petersen said.

However, despite dietitians’ lack of belief in the principles portrayed in “Sugar Busters,” it continues to be a bestseller.

An employee of Waldenbooks in North Grand Mall said the store has already sold about 50 copies.

Sylvia Sadowski of Walt’s Books, 620 Lincoln Way, said “Sugar Busters” has been a “big seller.”

“Diet books always sell well,” she said.