Q & A: Can Genetics Interfere with Weight Loss Efforts?

Q: One of my obese binge eating disorder patients absolutely insists that in spite of her diligent efforts at diet and exercise she simply can’t lose weight as easily as others in her group, and she blames this on her genetics. Could there be any truth to her assertions?
(F.P., Detroit)

A: The answer to your question, and to your patient’s plight, is actually complex. Some studies suggest that obese patients who can’t lose weight tend to underestimate and underreport their caloric intake. They do so not to be deceptive, but because they’re psychologically skewed to see the amounts of foods they’re consuming as less caloric than they actually are. That sort of perceptual and reporting bias probably accounts for the majority of the problem for most people. However, at the same time recent research suggests there may actually be some genetic differences that account for difficulties in losing weight. In a Japanese study, women with the Trp64Arg polymorphism of the 3adrenergic receptor gene, a type found in about 20% of the Japanese population but in fewer Caucasians, had more difficulty losing weight during a three-month behavioral diet and exercise intervention program than women with other genotypes. Among women with this genotype, 48% lost some weight, compared to 69% of the others. This gene variant was not associated either with initial obesity or initial resting energy expenditure. (Shiwaku K et al. Int J Obesity 2003; 27: 1028). Other genes may also prove to be influential in this regard. So, the answer to why some women appear to have more difficulty losing weight may ultimately depend on nature AND nurture.

J.Y.