Are You Fated to Be Fat?

Medically Reviewed by Melinda Ratini, MS, DO on June 16, 2015
3 min read

Your genes are why your eyes are brown and your hair is red. They’re what make you, well, you. But can genetics determine the size of your jeans?

Research shows that differences in your genes can lead to weight issues. So if your parents are obese, you’re more likely to be, too. But that doesn’t mean you will without question. Many people with obesity in their families don’t tip the scales. And you can fight the odds with diet and exercise.

There’s one gene that’s getting a lot of attention, called FTO. Scientists found that people with certain differences in this gene have a 20% to 30% higher chance of obesity. And those differences are pretty common.

Dozens of other genes are linked to weight as well. Some, for example, cause people to just naturally store more fat.

But it’s still unclear exactly how much weight genes really do carry. Are you really destined to be overweight?

“Obesity is a very complex disease, and many factors can contribute to it and cause it, including genetics, behavior, and environment,” says Naima Moustaid-Moussa, PhD, director of the Obesity Research Cluster at Texas Tech University. Obesity can run in families -- not because of genetics, but because of habits and environment, she says.

More than a third of adults in the United States are obese, Moustaid-Moussa says. “The number of Americans with obesity has steadily increased over the past five decades, but this can’t be explained by some dramatic changes in our genes.”

Jung Han Kim, PhD, an obesity researcher and professor at Marshall University’s Joan C. Edwards School of Medicine, agrees. Obesity has increased around the world with industrialization, a sedentary lifestyle, and a fat-filled diet, she says.

So can your lifestyle trump your genes?

“We know from research that some genetic predisposition increases your risk to be overweight and obese, but it can be overcome by lifestyle,” says Zhaoping Li, MD, PhD, director of the Center for Human Nutrition at the University of California, Los Angeles. “Genetics load the gun, environment pulls the trigger.”

And by environment, Li means the tried-and-true offenders like too much sitting and too much food.

Plus exercise is key. Research shows that even if you’re likely to be obese because of your genes, you can change course by breaking a sweat regularly.

Family history alone doesn’t seem to be enough to make you obese.

“Genetics does play a role, but the truth is who you are is still determined by how you live your life,” Li says.

So the same advice holds true:

  • Get active. Aim for 2 1/2 hours of moderate-intensity exercise like brisk walking every week. Even doing 10 minutes at a time helps. Weight training, done at least twice a week, will help make your muscles strong.
  • Eat less. Cut calories. Lopping off 500 to 1,000 a day can help you lose 1 to 2 pounds a week.
  • Choose good-for-you foods. Go for fruit, veggies, whole grains, and fat-free or low-fat dairy foods. Fish, lean meats, beans, eggs, and nuts are also good options.