High-Protein Diets May Be Harmful
trying one of the "new" high-protein diets to shave off some pounds?
You better think again, national health experts are saying.
diets have no proven effectiveness in long-term weight reduction and
pose potential health threats for those who adhere to them for more
than a short time, according to a new advisory from the American Heart
Association's nutrition committee.
which appeared in the Oct. 9, 2001, issue of "Circulation: Journal of
the American Heart Association," specifically targets some of the
popular "quick weight loss" regimens, many of which have become
best-selling books. It also offers guidelines to healthcare
professionals for evaluating such diets.
items may also be high in fat. Some of the diets increase fat intake
and reduce nutritionally rich foods such as fruits and vegetables,
which is not a good approach to meeting a person's long-term dietary
needs," said Dr. Robert H. Eckel, immediate past chair of the AHA's
nutrition committee and co-author of the advisory. "Many of these diets
fail to provide essential vitamins, minerals, fiber and other
nutritional elements, in addition to their high fat content."
said high-protein diets have not been documented to deliver sustained,
long-term weight loss, adding, "In general, quick weight-loss diets
don't work for most people."
shown consistently that successful maintenance of weight loss occurs
most often when people follow a nutritionally sound diet and increase
physical activity to burn more calories than they consume, stressed
Eckel, a professor of medicine at the University of Colorado Health
Science Center, Denver.
emphasized in some high-protein and similar diets are from animal
sources that are rich in protein and saturated fat, such as meat and
eggs. Meanwhile, some of the diets drastically limit consumption of
high-carbohydrate foods such as cereals, grains, fruits, vegetables and
low-fat milk products, Eckel said.
amounts of high-fat animal foods over a sustained period has been shown
to increase the risk of coronary heart disease, diabetes, stroke and
several types of cancer, he added.
the AHA statement, a diet rich in animal protein, saturated fat and
cholesterol raises LDL cholesterol levels -- an effect that is
compounded when high-carbohydrate, high-fiber plant foods that help
lower cholesterol are limited or eliminated.
"That is why
the American Heart Association urges most adults to limit fat intake to
no more than 30 percent of total daily calories, less than 10 percent
of which should be saturated fat," Eckel said. "On some of the
high-protein diets, meeting these goals is simply impossible."
A diet high
in complex carbohydrates that includes fruits, vegetables, non-fat
dairy products and whole grains has been shown to reduce blood
pressure, the statement continues. Limiting these foods, which are rich
in calcium, potassium and magnesium (nutrients associated with blood
pressure reduction), may lessen the benefit of weight loss on blood
proteins are essential nutrients required to maintain the body's
structure and proper function, most Americans already eat more protein
than their bodies need, and excess dietary protein can, in itself, also
increase health risks, Eckel stressed: "In some individuals with kidney
or liver disease, unneeded protein may put them at risk of worsening
What's at Work
diets induce a quick drop in weight primarily through loss of body
fluids caused by the diuretic effect of eliminating most carbohydrates,
Eckel explained. Glycogen, the form of sugar used by the body for
energy, is lost from the muscles as well, sometimes causing fatigue, he
said. In general, some of these diets also induce ketosis, a metabolic
condition associated with low blood levels of insulin that results when
the body is deprived of dietary carbohydrates. Sustained ketosis also
causes a loss of appetite, which may lead to lower total calorie
intake, he said.
high-protein diet is especially risky for patients with diabetes,
because it can speed the progression ... of diabetic renal disease,"
the statement added. "Some popular high-protein, low-carbohydrate diets
limit carbohydrates to 10-20 grams per day, which is one-fifth of the
minimum 100 grams per day that are necessary to prevent loss of lean