Weight-loss study based on bad science
Last Updated Aug 2007
The Journal of the American Medical Association (JAMA) has just published an
article in which researchers at Stanford University supposedly compared the impact
of four different diets for overweight women. They found that the Atkins diet was
superior to the other diets, including the Zone Diet. If you actually read the
study; however, you come to very different conclusions.
First, what the subjects ate in the JAMA study had no relationship to any of the
diet programs that were supposedly being tested. The protein, fat and carbohydrate
ratios were not accurate for any of the diets. Second, the absolute levels of
carbohydrates being consumed were also not consistent with any of the diets.
Specifically, the "Atkins Diet" used in the study was much higher in carbohydrate,
the "Zone Diet" was too low in protein and too high in carbohydrate, the "LEARN
Diet" was too low in carbohydrate, and the "Ornish Diet" was too high in fat. In
fact, the amount of carbohydrates consumed on the "Atkins Diet" during the study
was almost identical to the recommendations of the Zone Diet, which explains
why "Atkins" had the most favorable results.
An example of how careful science leads to a different conclusions can be found in
the May 2006 issue of the American Journal of Clinical Nutrition in which a
carefully controlled study I did in collaboration with Carol Johnson of Arizona
State University was reported. The protein, fat and carbohydrate amounts of the
diets studied were accurate, and all meals were prepared for the subjects. Not
surprisingly, that study found that the reductions in total cholesterol, LDL
("bad") cholesterol, and triglyceride levels were more favorable for the people
following the Zone Diet than for those following the Atkins Diet. This study was
an example of good science with poor publicity unlike the study published in JAMA,
which can be viewed as bad science with good publicity.
No wonder why Americans are confused.