Best Diet Determined By DNA Test

By Margarita Nahapetyan

A simple DNA test can now reveal whether a person is more likely to lose weight on a low fat diet or a low-carb diet, American scientists from Stanford University have reported this week.

For their study, the scientists analyzed data from 138 overweight or obese white Caucasian women, who provided DNA from a swab of their cheek cells. All women were assigned to one of four popular diets for a period of 12 months. The diets included: the Atkins diet (very low carbohydrate), the Zone diet (low carbohydrate with high protein), the Ornish diet (very low fat) or a health professional's diet (a low-fat diet that generally follows the U.S Agriculture Department's Food Pyramid).

Also, the researchers used the genetic information to assign the women to three genotypes, or "genotype-appropriate" diets, an eating plan that would seem to be the most effective for them, based on their particular genetic makeup. The genotypes were described by experts as low carbohydrate diet responsive, low fat diet responsive and a balanced diet responsive genotype.

The results revealed that, one year later, those women who were assigned to the correct diet plan based on their genotype, lost 2 to 3 times more weight, when compared to those women who were assigned to a diet that was "wrong" for them. When the experts analyzed only the most extreme diets, such as Atkins diet versus Ornish diet, the results were even more stark. Overall, the study found that women assigned to the appropriate diet for their genotype lost 5 times as much weight as women on the wrong diet. In addition, the women on the correct diets showed improvements in their "good" (HDL) cholesterol and reductions in harmful triglycerides.

"Knowing your genotype for low-carb or low-fat diets could help you increase your weight-loss success," said Christopher Gardner, an associate professor of medicine at Stanford and a co-author of the new research. The results of the experiment demonstrate that even strict adherence to a diet will never matter if a person's diet is out of synch with their genetics, Professor Gardner added.

The new findings help explain a common phenomenon in the weight-loss wars: why two individuals decide to lose weight and start the same diet and exercise plan, only to discover one of them to succeed, while the other one achieve nothing. However, the new results still need confirmation in a larger study, and additional research is also needed in order to more clearly determine the usefulness of the DNA test, including how it applies to men and people in different racial groups.

The results of the study were presented at the American Heart Association's annual epidemiology and prevention conference, and have just been submitted to a medical journal.