Atkins Diet - Effective As A Low-Fat Diet
Two new studies seem to provide further evidence that a low-carbohydrate
regimen is at least as effective as a low-fat diet in helping people
drop excess weight without harming their cholesterol levels.
The studies described in the May 18 issue of the Annals of Internal
Medicine support the late Dr. Robert Atkins, the controversial New
York cardiologist who popularized a high-protein, high-fat approach
that severely restricts carbohydrate consumption.
In both studies, low-carb dieters lost more weight at the end of
six months than people on a low-fat diet. They also had lower levels
of triglycerides -- blood fats that can raise the risk of heart
attack or stroke -- and improved levels of high-density lipoprotein
(HDL), the so-called "good" cholesterol.
After a year, people on the low-carb diet had better triglyceride
and HDL levels than those on a conventional low-fat diet, although
weight loss was similar between the two groups.
"Clearly, all of these studies show that a low-carb diet is
an option for people," said Dr. William S. Yancy, a research
associate at the Veterans Affairs Medical Center in Durham, N.C.,
and lead author of one of the studies.
Critics, however, remain unconvinced. These short-term studies
do not measure the potential long-term risk for heart disease, the
nation's top killer. Without solid evidence, no one really knows
whether the Atkins approach can produce lasting weight loss without
damaging the heart, they say.
"The public has been misled enough already," said Dr.
Robert H. Eckel, a nutrition spokesman for the American Heart Association,
and a professor of medicine and physiology at the University of
Colorado Health Sciences Center in Denver.
Skeptics also point to a potential conflict of interest. One of
the studies was supported by a grant from the Robert C. Atkins Foundation.
Atkins died in April 2003 after a severe head injury left him comatose,
but his unconventional weight-loss approach has persevered. The
Atkins diet gained new respect last May when two studies in the
New England Journal of Medicine suggested the plan is more effective
than a traditional low-fat diet in helping people shed unwanted
pounds without boosting their cholesterol levels.
The new studies seem to bolster those results.
One study is believed to be the longest and largest low-carb
vs. low-fat face-off to date, involving people with diabetes or
who are at high risk of cardiovascular disease.
Lead author Dr. Linda Stern, an internal medicine physician at
the Philadelphia Veterans Affairs Medical Center, and colleagues
followed 132 obese adults over a 12-month period. Eighty-three percent
of them had diabetes or metabolic syndrome, a combination of disorders
that can lead to greater risk of diabetes, heart disease, or stroke.
Participants were randomly assigned to either a restricted carbohydrate
diet -- less than 30 grams of carbohydrates a day -- or a conventional
diet that cut caloric intake by 500 calories a day, with less than
30 percent of calories from fat.
At six months, the low-carb dieters lost more weight than the low-fat
group. By 12 months, though, their weight loss was similar -- roughly
11 to 19 pounds for the low-carb group and seven to 19 pounds for
the low-fat group.
The difference is that the low-carb group maintained most of its
six-month weight loss over the year, while the low-fat group continued
to lose weight after six months. Another key difference is the low-carb
group's blood fat levels decreased more, and their good cholesterol
decreased less than the low-fat dieters.
The findings may be limited because of a high dropout rate, the
authors concede. Overall, 34 percent ended their participation before
the study was completed. Twenty were on the low-carb diet and 25
were on the conventional diet.
"I think at this point I have no compunctions recommending
to patients cutting out simple carbohydrates," Stern said.
The second study reported in the same issue of the journal followed
120 overweight people for six months. Low-carb dieters dropped an
average of 26 pounds, compared to an average of 14 pounds shed by
the low-fat group. The low-carb group also had greater decreases
in blood fat levels and greater increases in good cholesterol than
their counterparts on a low-fat diet.
Unlike other studies, people on the low-carb diet received daily
multivitamins and other nutritional supplements like those recommended
for people on the Atkins diet. One was an essential-oils supplement
containing 1,200 milligrams of fish oil, known for its heart-healthy
"This alone would account for lower triglyceride levels in
the low-carb group," noted Katherine Tallmadge, a nutritionist,
author, and spokeswoman for the American Dietetic Association. "Why
didn't they give the supplements to the low-fat group as well? If
they did, that group's triglycerides would have fallen, too."
So what's the bottom line for Americans struggling to trim down?
Do these studies vindicate an Atkins-like diet or give critics more
reason to vilify the approach?
Since study participants "self-reported" the food they
ate and how much physical activity they got, it isn't possible to
measure how many calories each group actually consumed and expended,
said Tallmadge. "In any case, if they lost more weight, they
were eating fewer calories," she concluded.
But in an editorial accompanying the two articles, Dr. Walter Willett,
professor of epidemiology and nutrition at the Harvard School of
Public Health, suggested that a low-carb diet may not be a bad way
"We can no longer dismiss very-low-carbohydrate diets,"
he wrote. Instead of choosing a diet that promises rapid weight
loss, people should find a way to eat that they can stick with over
time, he said. That may mean experimenting with reduced-carb diets,
as long as they emphasize healthy sources of fat and protein and
include regular physical activity, he cautioned.
People should see a doctor before starting any diet, particularly
if they are taking medications or have other health problems. While
a low-carb diet may end up being very good for these types of patients,
more study is needed, Yancy said.
Most people, though, can safely cut back on carbohydrates and have
beneficial results, Stern noted. "There's no precautions in
telling people to cut out soda and french fries, doughnuts, and
cookies. There's not a downside to that."