Low-Carb Diet

[Guest guest]

Low-Carb Diet

A synthesis of data from five previous clinical trials suggests that

both low-fat and low-carbohydrate diets appear to be effective for

weight loss up to one year, but low-carbohydrate diets may be linked

to higher overall LDL or " bad " cholesterol levels, according to a

study in the February 13 issue of the Archives of Internal Medicine,

one of the JAMA/Archives journals.

As obesity levels increase, more American adults are dieting-at any

one time, 45 percent of women and 30 percent of men are trying to

lose weight, according to background information in the article.

Those who succeed may reduce their risk of type 2 diabetes, control

their hypertension and decrease their chances of cardiovascular

disease and related death. Low-carbohydrate, high-protein diets have

become a popular alternative to the generally recommended low-fat,

calorie-restricted diet, the authors report. However, because these

diets contain large amounts of protein and fat, concern remains

about their effect on cholesterol levels and the cardiovascular

system, they write.

Alain J. Nordmann, M.D., M.Sc., University Hospital Basel,

Switzerland, and colleagues analyzed five previous clinical trials

that compared low-fat to low-carbohydrate diets. A total of 447

individuals with an average age ranging from 42 to 49 years

participated in the studies-222 on low-carbohydrate diets and 225 on

low-fat diets.

After six months, those on low-carbohydrate diets were more likely

to remain on the diet and had lost more weight than those on low-fat

diets. However, after 12 months, blood pressure, completion rates

and weight loss were the same for both groups. After six and 12

months, individuals on low-carbohydrate diets had increased total

cholesterol levels and LDL levels. However, they also had lower

triglyceride levels and higher HDL or " good " cholesterol levels.

" We believe there is still insufficient evidence to make

recommendations for or against the use of low-carbohydrate diets to

induce weight loss, especially for durations longer than six

months, " the authors write. " The differences in weight loss between

low-carbohydrate and low-fat diets after 12 months were minor and

not clinically relevant. "

Because no trials have yet examined the risk of heart attack or

death in people on low-carbohydrate diets, it's unclear whether the

beneficial effects low-carbohydrate diets appear to have on HDL and

triglyceride levels cancel out their apparent negative effects on

overall and LDL cholesterol levels, the authors write. " In the

absence of evidence that low-carbohydrate diets reduce

cardiovascular morbidity and mortality, such diets currently cannot

be recommended for prevention of cardiovascular disease, " they

conclude. (Arch Intern Med. 2006;166:285-293)