The Facts on Low-Carb Diets and Heart Disease
Atkins' Death Controversy Stirs Debate About the Safety of Low-Carb Diets
Feb. 11, 2004 -- Much like the controversy surrounding the
health of diet guru Robert Atkins, MD, at the time of his death last April, the
debate about the safety of the low-carbohydrate diet Atkins became famous for
isn't likely to calm down any time soon.
Critics of low-carb approach say the high-fat content of the
Atkins diet, which advocates meat, eggs, and cheese and limits bread, pasta,
and fruit, raises the risk of heart disease. But low-carb devotees say the
diets are safe and effective in promoting weight loss, which in turn lowers the
risk of heart disease.
But researchers say the facts boil down to this: There simply
isn't enough data on low-carb diets to support either argument.
"There are two extremes, but I think there is no evidence
to support either extreme in terms of benefits or harmful effects of this kind
of diet," says Frank Hu, MD, PhD, associate professor of nutrition and
epidemiology at the Harvard School of Public Health.
Many Questions, Few Answers
The prevailing view during the last 20 years has been that a
low-fat diet is the best way to achieve weight loss and reduce the risk of
heart disease. But the epidemic of obesity that the U.S. is currently
experiencing indicates that low-fat diets may not be the solution.
"The question now is whether the other extreme, a low-carb
diet, is the answer," says Hu.
During the "induction" phase of Atkins, in which
carbohydrates are most strictly limited, people typically consume as much as
60% of their calories from fat, including "bad" saturated fats from
animal sources that raise cholesterol levels and "good" unsaturated
fats, such as those found in olive oil and fish, which have favorable effects
on cholesterol profiles.
Although the Atkins diet has never specifically prescribed
recommended amounts of fat or protein, an Atkins educator recently told The
New York Times that only 20% of a dieter's calories should come from
Hu says getting even 20% of calories from saturated fat is
still too high. The American Heart Association and many other health
organizations recommend a maximum intake of 10% of total calories from
saturated fat in order to reduce the risk of heart disease.
"Based on what we know so far, you can expect that if you
eat this kind of diet for many years, there could be harmful effects on heart
disease and diabetes," says Hu. "The benefits of weight loss may
outweigh the potential harmful effects of saturated fat and cholesterol within
the short-term, but in the long-term we don't know."
The Evidence on Low-Carb Diets
Researchers hope studies currently underway will help answer
some of those questions about the safety of low-carb diets. Until then, only
short-term studies have addressed these issues.