Is obesity the result of genetics or lifestyle choices?

Eliza Kingsford, LPC
Nutrition & Dietetics

Obesity is caused by a combination of the genetic predisposition to overweight and unhealthy lifestyle choices. As more and more research emerges about  genes that contribute to excessive weight gain, it's clear that some are born with the pre-requisites for overweight. However, our culture promotes an obesegenic society that makes it difficult to stay at a healthy weight in the face of so many unhealthy choices. Portion sizes, processed foods, marketing and advertising budgets, weight loss gimmicks and fast food options all make making the unhealthy choice the "norm". Sedentary lifestyles due to a tendency to walk less, move less, sit in a boardroom more, sit in front of electronics more and drive more all contribute to the challenge to stay at a healthy weight. Since the mid seventies, Americans drive approximately 50% more and also consume approximately %30 more calories! Moving less and eating more is certainly leading us down the wrong path. However, we can't ignore the fact that "normal" weight people are also driving more and eating more. So why aren't they struggling with overweight? It is possible that they have a strict adherence to a health lifestyle. It is also clear that the people with a genetic predisposition to overweight are struglling more than ever to maintain a healthy weight. For these reasons, it is crucial that people who have been overweight or obese understand the barriers to success they face when trying to stay at a healthy weight. Without a consistent focus and commitment to healthy living and a more active lifestyle, weight control efforts often fail; the reason that FAD diets don't work. 

The consensus is that most cases of obesity are caused by eating too much and exercising too little.
Unhealthy eating habits - not having enough fruit, vegetables, whole grains, and so on - combined with overeating contributes the most to obesity.
Add to that a lifestyle without a regular exercise program and you have a recipe for obesity.
While there are some rare genetic conditions that can cause obesity, there is no reason why most people cannot lose weight. 
You may inherit your parents’ inability to burn calories at a rapid pace, referred to as slow metabolism. That may make it more challenging, but it does not make it unlikely that you can lose weight and keep it off.
Dr. Michael Roizen, MD
Internal Medicine
If you need to worry about losing 25, 35, even 50 pounds, your problem is not likely to be genetic. Only when your excess weight exceeds 100 pounds would most doctors consider testing for genetic abnormalities.)

Researchers argue that obesity is more genetically linked than any other trait except height—and at least 50 percent of obesity cases clearly have genetic components. This may help explain the 95-percent failure rate after two years of those people who lose 50 pounds or more: They had plenty of willpower to lose (it's the argument that lean people tend to make is that lifestyle choices and lack of willpower are responsible for obesity) but regained the weight nonetheless.

My take: The waist-control game requires two players—environment and genetics.

While 10 percent of the obese population has genetic challenges that may make a super-model contract impossible, the bigger risk with these genes is not in the weight itself, but the predispositions for risks associated with obesity.

Even if your genes have made you pre-destined for a life of taking up two seats, that doesn't mean you should abdicate control over your body. When you make the right behavioral and biological changes, you'll be able to stay healthy and avoid the bad side effects of obesity, like diabetes, high blood pressure, and arterial inflammation.
YOU: On A Diet Revised Edition: The Owner's Manual for Waist Management

More About this Book

YOU: On A Diet Revised Edition: The Owner's Manual for Waist Management

For the first time in our history, scientists are uncovering astounding medical evidence about dieting -- and why so many of us struggle with our weight and the size of our waists. Now researchers...

Continue Learning about Obesity

How Your Diet Now Can Affect Your Future Children
How Your Diet Now Can Affect Your Future Children
In 2007, the heaviest woman ever to give birth weighed in at 532 pounds and it took 30 doctors to perform the C-section. While she’s an extreme ex...
Read More
How many people die by being overweight or obese?
Arthur W. Perry, MDArthur W. Perry, MD
In this era of an obesity epidemic, interest in dieting is higher than ever before. Obesity is t...
More Answers
What is a bariatrician?
Craig B. Primack, MDCraig B. Primack, MD
There is a certification board for bariatricians (medical weight specialists) which have just receiv...
More Answers
Understanding the Obesity Pandemic
Understanding the Obesity Pandemic

Important: This content reflects information from various individuals and organizations and may offer alternative or opposing points of view. It should not be used for medical advice, diagnosis or treatment. As always, you should consult with your healthcare provider about your specific health needs.