Study Supports Atkins Diet Effectiveness
Atkins Dieters Lose More Weight In Short Term
UPDATED: 9:14 a.m. EDT May 22, 2003
A new study provides more evidence in favor of the Atkins diet.
Researchers say dieters on the low-carbohydrates Atkins diet lost twice as much weight at three and six months as people using a conventional high-carbohydrate, low-calorie approach to dieting.
In addition, researchers found that Atkins dieters had significantly greater increases in levels of HDL -- the "good" cholesterol -- and decreases in triglycerides.
But during the second six months, dieters on both plans tended to regain weight, and there was no statistical weight difference between the groups at one year.
The study, conducted by researchers from Washington University School of Medicine in St. Louis, the University of Pennsylvania School of Medicine in Philadelphia, and the University of Colorado Health Sciences Center in Denver, is published in Thursday's issue of the New England Journal of Medicine.
A similar study led by a researcher at the Philadelphia Veterans Affairs Medical Center was also published in the journal issue.
"Our results may be surprising to some people," said Dr. Linda Stern, a researcher from the University of Pennsylvania School of Medicine. "Diabetics in particular did very well on the low-carbohydrate diet. So, especially in the realm of lifestyle modification, we might have to broaden our horizons on what we're recommending."
All of the study's 63 volunteers had medically significant obesity, meaning that they weighed at least 20 percent more than their ideal body weight. The participants had an average age of 44 and weighed an average of 216 pounds.
The researchers wanted to mimic real dieting, so they didn't offer behavioral therapy. Instead, study participants met with a registered dietician at the beginning of the study, and then again at three, six and 12 months into the program.
Those in the Atkins group received a copy of Dr. Atkins New Diet Revolution and were asked to follow the diet as described. The conventional diet group received instructional materials on how to maintain a diet that consisted of 60 percent carbohydrates, 25 percent fat, and 15 percent protein, based on the Food Guide Pyramid.
At three months, Atkins dieters lost an average of 17.6 pounds, compared with 8.3 pounds in the conventional diet group. At six months, Atkins dieters lost 21.1 pounds, compared to the conventional dieters' 11.5 pounds.
At 12 months, the Atkins diet group was down an average of 15.9 pounds versus 9.7 pounds for those on the conventional diet. The difference is not considered statistically significant, partly because almost half of the participants dropped out of the study before the one-year mark.
"While it is premature to widely recommend low-carbohydrate diets, these initial findings suggest that such diets may not have such detrimental effects on cholesterol as was originally thought to be the case," said Dr. Holly Wyatt, of the University of Colorado Health Sciences Center.
The safety and effectiveness of the Atkins diet, which limits carbohydrates but permits unrestricted amounts of protein and fat, has been under debate by health professionals since it was first introduced in the early 1970s.
The eating plan was advocated by the late Dr. Robert Atkins, the well-known diet doctor who died last month. Atkins advised patients to cut down on carbohydrates, especially refined carbohydrates, and not to worry about saturated fat -- butter, cream, steak -- as long as they were limiting carbohydrates.
Because of the high amounts of fat that people consume on the Atkins diet, many have worried that over the long term, it might have serious side effects. Although the researchers found no differences in side effects during the 12 months of this study -- and even found benefits in blood lipid profiles -- they say they will look more closely at potential side effects in their next study.
"A calorie is still a calorie, whether the calorie comes from fat, carbohydrates or protein," said Dr. Samuel Klein, senior researcher from Washington University School of Medicine. "But it might be that certain types of calories are more filling than others and result in an overall decrease in total calorie intake."
However, the researchers say longer and larger studies are needed to assess the long-term safety and efficacy of low-carbohydrate, high-protein, high-fat diets.
The same research team will recruit larger numbers of participants in a five-year study of low- and high-carbohydrate diets funded by the National Institutes of Health. The researchers hope to more fully assess the benefits and risks of the diets on bone mass, kidney function, blood vessel health and exercise tolerance. They also will look at whether behavior intervention and modification might help people stick to these diets.
But food intake isn't everything. Even the best diet must be combined with other lifestyle changes, such as increased physical activity, to combat obesity, Stern said.
"Half the equation is to get people to be aware of what they're eating, and to eat less," Stern said. "The other half is to get them to move. Any weight loss program ... must include a formal exercise program."
The study was funded through grants from the National Institutes of Health General Clinical Research Centers at the University of Pennsylvania, Washington University, and the University of Colorado Health Sciences Center/Center for Human Nutrition.
Those in the Atkins group received a copy of Dr. Atkins New Diet Revolution and were asked to follow the diet as described. The conventional diet group received instructional materials on how to maintain a diet that consisted of 60 percent carbohydrates, 25 percent fat, and 15 percent protein, based on the Food Guide Pyramid.
At three months, Atkins dieters lost an average of 17.6 pounds, compared with 8.3 pounds in the conventional diet group. At six months, Atkins dieters lost 21.1 pounds, compared to the conventional dieters' 11.5 pounds.
At 12 months, the Atkins diet group was down an average of 15.9 pounds versus 9.7 pounds for those on the conventional diet. The difference is not considered statistically significant, partly because almost half of the participants dropped out of the study before the one-year mark.
"While it is premature to widely recommend low-carbohydrate diets, these initial findings suggest that such diets may not have such detrimental effects on cholesterol as was originally thought to be the case," said Dr. Holly Wyatt, of the University of Colorado Health Sciences Center.
The safety and effectiveness of the Atkins diet, which limits carbohydrates but permits unrestricted amounts of protein and fat, has been under debate by health professionals since it was first introduced in the early 1970s.
The eating plan was advocated by the late Dr. Robert Atkins, the well-known diet doctor who died last month. Atkins advised patients to cut down on carbohydrates, especially refined carbohydrates, and not to worry about saturated fat -- butter, cream, steak -- as long as they were limiting carbohydrates.
Because of the high amounts of fat that people consume on the Atkins diet, many have worried that over the long term, it might have serious side effects. Although the researchers found no differences in side effects during the 12 months of this study -- and even found benefits in blood lipid profiles -- they say they will look more closely at potential side effects in their next study.
"A calorie is still a calorie, whether the calorie comes from fat, carbohydrates or protein," said Dr. Samuel Klein, senior researcher from Washington University School of Medicine. "But it might be that certain types of calories are more filling than others and result in an overall decrease in total calorie intake."
However, the researchers say longer and larger studies are needed to assess the long-term safety and efficacy of low-carbohydrate, high-protein, high-fat diets.
The same research team will recruit larger numbers of participants in a five-year study of low- and high-carbohydrate diets funded by the National Institutes of Health. The researchers hope to more fully assess the benefits and risks of the diets on bone mass, kidney function, blood vessel health and exercise tolerance. They also will look at whether behavior intervention and modification might help people stick to these diets.
But food intake isn't everything. Even the best diet must be combined with other lifestyle changes, such as increased physical activity, to combat obesity, Stern said.
"Half the equation is to get people to be aware of what they're eating, and to eat less," Stern said. "The other half is to get them to move. Any weight loss program ... must include a formal exercise program."
The study was funded through grants from the National Institutes of Health General Clinical Research Centers at the University of Pennsylvania, Washington University, and the University of Colorado Health Sciences Center/Center for Human Nutrition.
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