Although scientists have discovered more than 50 genes that influence weight, one appears to be chief among them: the fat mass and obesity-associated gene, also known as the FTO gene.

The FTO gene was the first gene to be associated with obesity risk. In 2007, researchers discovered that individuals with a certain FTO variant tended to be overweight. Since then, multiple studies have confirmed the relationship between FTO variants and obesity. One FTO risk variant affects 42 percent of caucasians, while two other risk variants affect Africans and Asians.

Because people have two copies of each gene — one from each parent — a person can have one or two FTO risk variants. On average, one copy of the risk variant equates to 3.5 additional pounds of body weight. Two risk variants lead to 7 additional pounds and increase a person’s risk of obesity by 50 percent.

But research also indicates that the FTO gene hasn’t always been a problem. If scientists had looked at the relationship between FTO and weight a few decades ago, they wouldn’t have seen the same connection. That’s because the FTO variant became an obesity risk only in people born after 1942.

These findings raise questions about how much of our health is determined by genetics, and how much is influenced by our environment. Often, it is the relationship between the two that determines whether we’re at risk for obesity, cancer, or other degenerative disease. Our environment, particularly our diet and certain other lifestyle factors, can act as a switch that turns gene expression on or off. For instance, a gene variant associated with psychosis is a problem only if the individual uses cannabis.

Our environment has changed drastically in many different ways over the past 100 years: we eat different foods, we’re exposed to different chemicals and pollutants, and advances in technology mean that we’re far more sedentary. Researchers involved in the 2014 FTO study wanted to see how all of these changes affected gene expression. To evaluate the effects of the FTO gene over time, they used data from a study that began in 1948. The Framingham Heart Study originally followed the health of 5,000 participants, and eventually recruited their children and grandchildren. When looking at genetic information of the participants, researchers confirmed that those with the FTO variant weighed more. But when comparing the data of people born in different eras, researchers made some surprising discoveries. People with the FTO variant who were born prior to 1942 were not at an increased risk of obesity. And the younger the participants were, the greater their obesity risk.

The researchers suspected that certain changes in our environment have made people more susceptible to the effects of the FTO gene. Most likely, decreased physical activity is to blame. Prior to World War II, people were more physically active, which may have protected them from FTO’s obesity risk. The modern diet could also be a factor: people with the FTO variant who consume fried foods and sugary beverages gain more weight than people who eat the same diet but do not have the FTO variant.

Fortunately, we have control over many of these environmental factors. People with the FTO risk variant are advised to exercise regularly, which can cut their risk of obesity by more than 50 percent. Adopting a genetically appropriate diet can also help individuals with the FTO variant control their weight: people with one FTO risk variant may lose weight more effectively on a low-fat diet, while people with two risk variants may also benefit from higher protein consumption.

You can find out if you carry the FTO variant and also learn your ideal diet type with your genetic report from Vivaliti DNA. Your 49-page report reveals several genetic factors related to weight so that you can reduce your risk of obesity and weight-related disease. Order your genetic test now!