This article is a rebuttal to the last article I sent. Written by a
Times reporter.
http://www.nytimes.com/2016/09/16/health/type-2-diabetes-low-carb-diet.html
Diabetes and Your Diet: The Low-Carb Debate
By GINA KOLATA SEPT. 15, 2016
A few years ago, Richard Kahn, the now-retired chief scientific and
medical officer of the American Diabetes Association, was charged
with organizing a committee to prescribe a diet plan for people with
diabetes. He began by looking at the evidence for different diets,
asking which, if any, best controlled diabetes.
"When you look at the literature, whoa is it weak. It is so weak,"
Dr. Kahn said in a recent interview.
Studies tended to be short term, diets unsustainable, differences
between them clinically insignificant. The only thing that really
seemed to help people with diabetes was weight loss - and for weight
loss there is no magic diet.
But people want diet advice, Dr. Kahn reasoned, and the association
really should say something about diets. So it, like the National
Institutes of Health, went with the Department of Agriculture's food pyramid.
Why? "It's a diet for all America," Dr. Kahn said. "It has lots of
fruits and vegetables and a reasonable amount of fat."
That advice, though, recently came under attack in a New York Times
commentary written by Sarah Hallberg, an osteopath at a weight loss
clinic in Indiana, and Osama Hamdy, the medical director of the
obesity weight loss program at the Joslin Diabetes Center at Harvard
Medical School.
There is a diet that helps with diabetes, the two doctors said, one
that restricts - or according to Dr. Hallberg, severely restricts -
carbohydrates.
"If the goal is to get patients off their medications, including
insulin, and resolve rather than just control their diabetes,
significant carb restriction is by far the best nutrition plan," Dr.
Hallberg said in an email. "This would include elimination of grains,
potatoes and sugars and all processed foods. There is a significant
and ever growing body of literature that supports this method." She
is in private practice at Indiana University Health Arnett Hospital
and is medical director of a startup developing nutrition-based
medical interventions.
But there are no large and rigorous studies showing that low
carbohydrate diets offer an advantage and, in fact, there is not even
a consensus on the definition of a low-carbohydrate diet - it can
vary from doctor to doctor.
"There have been debates for literally the whole history of diabetes
about which kind of diet is best," said Dr. C. Ronald Kahn, chief
academic officer at Joslin, and no relation to Dr. Richard Kahn. But,
he said, "the answer isn't so straightforward."
In support of a diet like Dr. Hallberg's, there is one recent short
term study by Kevin Hall of the National Institute of Diabetes and
Digestive and Kidney Diseases and his colleagues involving 17
overweight and obese men, none of whom had diabetes. They stayed in a
clinical center where they ate carefully controlled diets. The
researchers asked what would happen if calories in the diet were kept
constant but the carbohydrate composition of a diet varied from high
to very low. The answer was that insulin secretion dropped by 50
percent with the very low carbohydrate diet, meaning that much less
insulin was required to maintain normal blood glucose levels. "Since
diabetes results when the body can't produce enough insulin, perhaps
it is a good idea to reduce the amount of insulin it needs by eating
very low carbohydrate diets," Dr. Hall said.
Some longer term studies, though, failed to show that low
carbohydrate diets benefited glucose control.
Even if diets are effective in the short term, Dr. Hall said, "the
difficulty is adhering to the diet over the long term."
In an analysis of weight loss diets (not specifically for diabetics)
published this summer, he and Yoni Freedhoff of the University of
Ottawa wrote: "Diet adherence is so challenging that it is poor even
in short-term studies where all food is provided. When diets are
prescribed, adherence is likely to diminish over the long term
despite self-reports to the contrary."
But short term studies of just a few weeks - which constitute the
bulk of the diet studies - can be misleading, said Dr. C. Ronald Kahn.
"In the short term, the low carbohydrate diet sometimes does better
on glycemic control," he said. "But as time progresses the difference
mostly disappears. What counts is which diet helps most with long
term weight loss. "
The reason the advantage that is sometimes seen with a low
carbohydrate diets tends to vanish, Dr. C. Ronald Kahn added, is
probably a mixture of people failing to adhere to the diets and their
bodies adjusting to them.
Another issue with low carbohydrate diets, researchers said, is the
question of what will happen to overall health if diabetics actually
follow the diet for years or decades. (Heart attacks are the major
killer of people with diabetes.) Insulin levels may be better but,
said Dr. Rudolph Leibel, co-director of Columbia University's Naomi
Berrie Diabetes Center, "effects of a low carbohydrate diet on
lipoproteins and vascular biology could offset such a 'benefit.'" In
other words, it is not clear if a lower insulin level would translate
into fewer heart attacks.
Dr. Hamdy, whose recommended low carbohydrate diet is less
restrictive than the one Dr. Halberg suggests, reports that many
patients in his clinic have been able to stay with the diet for as
long as five years, losing weight and keeping it off. He presented
his study at the 2015 annual conference of the American Diabetes
Association and has submitted it for publication. It involved 129
patients. Half were able to lose weight and keep it off, and those
who did maintained an average weight loss of 9.5 percent. Their
diabetes was much improved.
It is impossible, Dr. Hamdy said, to separate weight loss from the
diet's effects on diabetes because people following such a diet -
which limits but does not forbid limits things like breads and pasta
and rice - also lose weight.
But multiple studies have found that when it comes to weight loss -
the only proven way to help with blood sugar control over the long
term - there is no difference between diets that restrict calories,
or fat, or carbohydrates.
Experts like Dr. David Nathan, director of the diabetes center and
clinical research center at Massachusetts General Hospital and a
professor of medicine at Harvard Medical School, advise dieting for
people with diabetes. But, he said, "when we advise people to be on
diets, the major goal is to lose weight."
What matters the most for controlling diabetes, Dr. Nathan said, "is
how much weight you lose."
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