Most popular diet plans not always most effective

Weight-loss plans are popular in today's society. Doctors and nutritionists are continuously developing new diets, feeding the consumer desire to be thin. Despite the multitude of options, however, most dieters remain ignorant of the nutritional aspects of the plans they have chosen.

A new study conducted at the University of Massachusetts Medical School aims to provide knowledge about popular diets. Researchers analyzed the dietary quality of eight common weight-loss plans including New Glucose Revolution, two Weight Watchers plans, Atkins, South Beach, Zone, Ornish and the 2005 Food Guide Pyramid.

The study, published in the Journal of the American Dietetic Association last Monday, said the Ornish plan is the best in terms of nutritional quality and heart-healthy benefits. The diet consists mainly of fruits, vegetables and fiber while eliminating saturated and trans fats. The Weight Watchers High-Carbohydrate plan and the New Glucose Revolution plan also scored in the top three.

The Atkins diet scored low on the list because of the high intake of saturated and trans fats due to encouraged consumption of red meat.

Yunsheng Ma, the study's lead author and an assistant professor of medicine at the University of Massachusetts Medical School, said any of the diets can help people lose weight but it is important to look at other health factors.

"The main benefit in the top-scoring diets is the reduced risk of cardiovascular disease," Ma said.

Ma and his colleagues chose six of the diets from The New York Times bestseller list, he said. The 2005 Food Guide Pyramid was chosen because it is the standard of dietary guidelines for all Americans, and the Weight Watchers plan is the largest commercial plan in the United States.

The researchers looked at the menus inside each of the books, Ma said. Each menu had a seven-day meal plan and the food information was entered into a nutritional database. The data consisted of the number of calories in each meal, the number of calories from fat and the serving size of fruits, vegetable, fiber and meat. This information labeled each diet plan with a nutrient score.

"From the nutrient score, we calculated the Alternate Healthy Eating Index," he said. "We use this index to rate the different dietary plans."

Ma said the AHEI assesses the dietary and heart benefits of different diets based on the amount of fruits, vegetables, fiber and meat each plan incorporates, as well as the ratio of good, polyunsaturated fats to bad, saturated fats. The index is on a scale from 0 to 70.

The Ornish diet received the highest score at 64.6, followed by Weight Watchers High Carbohydrate plan and the New Glucose Revolution diet, which both scored a little more than 57 points, he said.

The Atkins Plan, and other high-protein, low-carbohydrate diets did not score as high and are considered less beneficial for the heart, Ma said.

He said he was surprised the 2005 USDA Food Pyramid landed in the middle with a score of 48.

"This is what we were thinking should be on top, because it is a recommendation for every American," Ma said.

In the future, Ma and his colleagues may conduct a study focusing on how people follow different diets, he said.

"The Zone diet has a very low calorie intake, around 1,000, and I think it is hard for people to stick with it," Ma said.

The AHEI would be a useful tool for people to calculate what they are eating on a daily basis, he said.

"I can possibly work with a software company or computer engineer to develop an index for the computer," Ma said. "This would allow people to see how healthy their diet is."

Steven Stanhope, nutrition and dietetics professor at the university, said when a study is based on an index, results could be biased.

"The index value may be sensitive to the quantities that the diets pick," Stanhope said. "Details like that are important to look at to see if this seems to be a very fair and across-the-board assessment."

Oscar Galvis, board-certified physician and weight-loss specialist at Christiana Weight Loss Center, said there is no such thing as a good, healthy diet.

"Diets don't work," Galvis said. "They might work over time but it's physiologically impossible to maintain weight after a starvation-type diet."

He said he considers all diets included in the study to be starvation diets. Caloric restrictions slow down the metabolism.

"The bottom line is all these diets, in a disguised way, are cutting back on the amount of calories you take in so you lose on average two to three pounds per week," Galvis said. "Realistically, you are not going to stay on the diet for more than a month at time before you go back to your traditional way of eating.

"When you revert back to your normal way of eating, you will start gaining the weight back."

All of the diets included in the study are unhealthy because they deprive people of certain essential food groups, he said.

"The Weight Watchers with the point system is the best one if I had to choose," Galvis said. "However, if you talk to someone from Weight Watchers and ask how much weight they recommend you lose per week, they would say two to three pounds, and that is a starvation diet."

He said he recognized the importance of losing weight and eating healthily to benefit the heart, but it is important to lose the weight slowly and keep it off permanently.

"I tell patients to eat a little less and exercise a little more," Galvis said. "I recommend they lose two to three pounds per month. The key to losing weight is at a slow, gradual pace - not slowing down your body's metabolism."

Mariam Basma, nutritionist at Student Health Services, said she sees students who have been on these diets and have had trouble sticking with them or seeing results.