Is Genetic Risk of Obesity Really So Hard to Grasp?

C’mon Medscape. Genes are no excuse for obesity? Is that the best you can do with a fine study of obesity, diet, and genetic risk? Sadly, Medscape’s bias about obesity is showing. That’s because the website translated hope for overcoming obesity into a finger wagging headline about excuses.

Highly Heritable, Poorly Understood

Scientists have long known that obesity is highly heritable. Estimates are that the heritability is more than 70%. For reference, note that SNPedia reports heritability estimates for breast cancer that range between 25 and 56%. Many people have a hard time accepting these facts.

Let’s be clear. The point of research on genetic risks is not excuses. Rather, the point is to look for clues that will lead to solutions. You see, genes that make a person susceptible can become a target for therapies to control the disease.

Genes Define Our Biology, Not Our Destiny

The research prompting Medscape’s offensive headline is observational. So, it has all the weaknesses that come with such studies. But it is quite a careful study of the of how diet, genetic risk, and weight gain interact over time. Fortunately, the results provide reasons for optimism. Healthy dietary habits can help overcome genetic risks of obesity.

For their study, researchers looked at dietary patterns in people from two large data sets. Those were the Nurses Health Study and the Health Professionals Follow-up Study. They calculated genetic risk scores and measured changes in weight over a 20-year period. Their findings showed that people following a healthier pattern of eating had a lower risk of gaining weight. In fact, it was lower than their genetic profile alone would have suggested.

No surprise. Obesity results when genes, environment, and behaviors interact. Genes play the biggest role because they define our susceptibility. But it’s the environment and our responses that get the last word.

In an editorial, Louisa Ells and colleagues offer confidence. They tell us that genetic susceptibility is no reason for despair. Everyone has options. And certainly, policymakers have the option to offer better responses in healthcare and in public health strategies.

Click here for the study and here for the editorial.

Headache, photograph © openDemocracy / flickr

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January 13, 2018

2 Responses to “Is Genetic Risk of Obesity Really So Hard to Grasp?”

  1. January 13, 2018 at 9:50 am, John DiTraglia said:

    My reading of the report is that if they ate right people with the highest risk of obesity gained an average of 1 lb less every 4 years than not eating right. Five lbs over 20 years. It was about a third of a pound overall. This is small, observational, and it would stand to reason that people who were the most prone would be trying the hardest to eat “right.” i.e. reverse causality. The BMI results that are proportional to overall size are even smaller even though highly statistically significant that is the nature of the beast.

    That is plenty reason for despair.

    • January 13, 2018 at 9:59 am, Ted said:

      Thanks, John. Your insight is good.

      I’m not big on despair, nor am I big on using an observational study for evidence of treatment efficacy.

      What we know from well controlled studies is that good nutrition and lifestyle support can help people maintain a 5-10% lower weight. No miracles, but better health and quality of life. People also have options for better health without losing weight or for more intensive obesity care. Plenty of options. No need for despair.