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The Role of Genetics in Weight and Why One-Size-Fits-All Diets Don’t Work: Part 2

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Part 2: Are There Fat Genes?

It is easy to assume that someone who is overweight simply eats too much and/or doesn’t exercise. And while diet and exercise are the primary factors contributing to weight gain, genetics also play a role. Scientists have known for years that there are genes and genetic mutations linked to weight gain and obesity, but until recently, they didn’t know just how those genes affect weight.

FTO — Research led by scientists at MIT and Harvard University that was published online this week by the New England Journal of Medicine reveals that a faulty version of FTO causes the body to store energy from food as fat rather than burning it off.

“For the first time, genetics has revealed a mechanism in obesity that was not really suspected before,” said study leader Melina Claussnitzer, a genetics specialist at Harvard-affiliated Beth Israel Deaconess Medical Center.

This discovery relating to the FTO gene show that diet and exercise aren’t the only factors that feed into obesity. “A lot of people think the obesity epidemic is all about eating too much,” said Dr. Clifford Rosen, a scientist at Maine Medical Center Research Institute and an associate editor at the New England Journal of Medicine.

According to researchers from the National Institutes of Health, people who carry one or two of the mutated genes (either from one parent or both) have reduced function in their medial prefrontal cortex, a region thought to be important in controlling impulses and response to the taste and texture of food. People who carry one or two copies of this gene are more likely to consume high-calorie, fatty foods as they age.

One study of nearly 700 participants found that about 45 percent of people have at least one copy of the FTO variant, and about 16 percent of people have two copies of the gene.

MC4R — Overeating is largely responsible for overweight and obesity cases in modern society, and this genetic mutation is at least partially responsible for overeating in individuals who carry one or two of the MC4R mutation.

Mutations in this gene account for six to eight percent of obesity cases, and about 22 percent of the population has this mutation, making it the most common genetic cause of obesity. MC4R is responsible for increased appetite and decreased satiety. Carriers of this gene have a tendency to eat larger amounts of food, more fatty foods, and snack more frequently.

The most effective weight loss strategy for people with one or two MC4R variants is calorie restriction through portion control and making smart, healthy food choices.

Even if you are genetically predisposed to be overweight or obese, don’t let that become your excuse. Having one of these genetic mutations doesn’t destine you to become obese. Genetics are not your destiny; they are a propensity. Genetics load the gun; lifestyle, diet, and environment pull the trigger.

Betty Murray, CN, IFMCP, CHC is a Certified Nutritionist & Certified Functional Medicine Practitioner with the Institute for Functional Medicine, founder of the Dallas-based functional medicine clinic Living Well Dallas and Executive Director of the the Functional Medicine Association of North Texas. A master of the biochemistry of the body, Betty teaches her clients how to utilize nutrition for autoimmune diseases, digestive disorders, MTHFR and weight loss. You can find her book “Cleanse: Detox Your Body, Mind & Spirit” on Amazon here.

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