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Longest scientific study yet backs Atkins diet
12:21 18 May 04
NewScientist.com news service
The claimed benefits of the controversial low-carbohydrate
Atkins diet have been reaffirmed in two new studies, one of
which is the longest study to date.
"I think it's good news for Atkins dieters," says Linda
Stern, who led the first study of 132 obese patients at the
Veterans Affairs Medical Center in Philadelphia, US.
The diet was devised by the late US doctor Robert Atkins. To
lose weight, devotees avoid carbohydrates and consume more
protein and fat instead.
Both new studies found that subjects on the Atkins diet shed
significant amounts of weight without harmful effects on
blood fats and sugars. But the studies have failed to
silence critics of the diet, who want the US government to
investigate alleged adverse effects.
Stern's year-long study (Annals of Internal Medicine, vol
140, p778) was twice the length of any previous study. Half
the patients followed the Atkins regime, limiting daily
carbohydrate intake to just 30 grams. The rest tried losing
weight through a conventional low-fat diet much richer in
carbohydrates.
By the end, both groups had lost about the same amount of
weight, between five and eight kilograms for the Atkins
group and three and eight kilos for the low fat group. But
the Atkins dieters lost almost all their weight in the first
six months, then remained at a steady weight.
Stern says that this pattern of rapid weight loss matches
that seen in an earlier but shorter study of Atkins dieters,
by Gary Foster's team at the University of Pennsylvania in
May 2003. "I'm impressed that they didn't gain it all back,"
says Stern.
Compared with the low-fat group, Atkins dieters also had
lower levels of triglycerides, potentially harmful blood
sugars which can trigger heart disease. Concentrations of
beneficial high density cholesterols (HDLs) also held up
better in the Atkins group. And these favourable changes
remained till the end of the study, suggesting that there
might be lasting benefits.
"But what we really need is a study showing whether people
on the low-carbohydrate diet for years have different odds
of heart attacks, strokes and diabetes," she says.
A second, six-month study on 120 overweight patients at
Duke University Medical Center in Durham, North Carolina,
echoes the first, with low-carbohydrate dieters shedding an
average of 12 kilos, twice that lost by those on a low-fat
regime (Annals of Internal Medicine, vol 140, p769). And
the pattern of blood fats and sugars mirrored that in
Stern's study.
"Over six months, the diet appears to be relatively safe,
but we need to study the safety for longer durations," says
Will Yancy, head of the Duke team.
But critics highlight some negative findings from the Duke
study. "This new evidence confirms that levels of 'bad'
cholesterol worsen in a substantial number of low-
carbohydrate dieters," said Neal Barnard of the Physicians
Committee for Responsible Medicine, a vegan lobby group in
Washington DC.
"And the supposedly dramatic benefits of the diet do not
hold up over the long term," said Barnard, referring to the
end of weight loss after six months in the Stern study.
Although broadly supportive of the Atkins regime, Yancy
warns that the diet could pose risks including the
higher "bad" cholesterol, bone loss and kidney stones.
Because of this, he discourages first-time dieters from
using the regime.
Andy Coghlan
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news.bbc.co.uk3722221.stmOpen ↗
Scientists endorse Atkins diet
Following a low-carbohydrate, high-protein diet is a more
effective way to lose weight than following a low fat diet,
say US researchers.
Two studies published in the journal Annals of Internal
Medicine found weight loss was greatest when people followed
an Atkins-style diet.
Cholesterol levels also seemed to improve more on a low-carb
diet compared to a low-fat diet.
However, the research was funded by the Robert C Atkins
Foundation.
And critics say there are still serious doubts about the long-
term effect on health of adopting such diets.
In the first study, researchers at Duke University Medical
Center in Durham, North Carolina, assigned 120 obese
volunteers to either a low-carbohydrate, high-protein diet
or a low-fat, low-cholesterol, low-calorie diet.
After six months, the people on the Atkins-style diet had
lost an average of 26 pounds, compared to an average of 14
pounds in the conventional low-fat diet group.
The low-carbohydrate, high-protein diet also had a good
effect on fat levels.
The Atkins dieters lost more body fat, lowered their
triglyceride levels and raised their "good" HDL cholesterol
levels more than the low-fat dieters.
In the second study, researchers at the Veterans Affairs
Medical Center in Philadelphia followed 132 obese adults
who were randomised to either low-carbohydrate or low-fat
diet groups.
Again, after six months the people following the low-
carbohydrate diet lost the most weight and had improved
fat levels.
However, at 12 months both groups had lost similar amounts
of weight.
The low fat group had continued to lose weight from six to
12 months while the average weight in the low-carbohydrate
group had remained steady after six months.
Lead author of the Philadelphia study Dr Linda Stern said:
"I think a low-carbohydrate diet is a good choice because
much of our overeating has to do with consumption of too
many carbohydrates."
But she said more research was needed to see if a low-
carbohydrate diet remained safe and effective over the
longer term.
In an accompanying editorial, Dr Walter Willett, from the
Harvard School of Public Health in the US, said: "We can no
longer dismiss very-low-carbohydrate diets."
But he added that such diets should include healthy sources
of protein and fat and incorporate regular exercise.
"Patients should focus on finding ways to eat that they can
maintain indefinitely rather than seeking diets that promote
rapid weight loss," he said.
Dr David Haslam, chairman of the National Obesity Forum,
said: "There is no doubt that if low-carbohydrate, high-
protein diets are followed properly you will lose weight.
"What's always been questioned is the long term efficacy of
such diets and in the short term, with weight loss, there
are certain risks in certain patients - like patients with
renal problems."
"There's still no long term data about the efficacy and you
can't stick on that type of diet for long because it's
unpalatable," he said.
Dr Haslam called for more research spanning five to six
years rather than months.
He said the best diet was still a healthy, balanced diet
cutting out excessive fat.
"One thing the Atkins isn't is balanced. It's not what the
body expects and that's why we don't know the long term
changes," he said.
Dietzmina Govindji, of the British Dietetic Association,
also warned people against thinking Atkins, or other similar
diets, were the best way to lose weight.
She said: "Do not be sucked in by the cabbage soup diet and
other fad diets.
"The thing to remember about all these quick-fix diets is
they do help you lose weight very, very quickly but often
you will put it back on very, very quickly and they often
miss out on whole food groups, so you are not getting the
full range of vitamins and minerals you need."