Struggling to find the perfect pair of jeans? Feel like you're losing the battle of the bulge? Don't blame yourself, blame your mother or your grandmother. Turns out your genetic makeup could effect your body weight.

In a paper published by UT Southwestern Medical Center, researchers discovered a gene that determines how we accumulate body fat. If you're lucky (or I should say blessed) with the right form of this miracle gene, gaining weight is hard for you. But, if you're unlucky (or I should say cursed) with another form of the gene, gaining weight is easy and hard to take off.

That study found a clear association between variations in a gene called "FTO" on chromosome 16, and variation in weight, body fat, and type 2 diabetes in nearly 40,000 white Europeans. More than half the study population had one copy of the version of the FTO gene associated with obesity. Roughly 16% had two copies of this version of the gene and were, on average, about 7 pounds heavier than counterparts with two copies of the low-risk version of the gene.

There is one way in which this study, and the new one from the Texas researchers, not to mention the prior knowledge we had of at least 100 genes involved in weight regulation, may be of use to you. It might help you avoid blaming yourself, or allowing others to blame you, for difficulty in controlling your weight.

Many times over the years, I have had patients tell me, often on the brink of tears, that they tend to gain weight even though they eat the same amount, and exercise the same amount, as someone else who stays thin. They tell this tale as if seeking confirmation, and redemption.

I have always been able to provide it, because I know that susceptibility to weight gain varies considerably. Our bodies use calories in three ways: physical activity, the generation of heat, and basal metabolism. Only the first of these is under our control, and accounts for just 15% or so of total daily energy expenditure. The remaining 85% is under genetic control, something we have long known even without identifying the specific genes involved.