Skip to content
My WebMD Sign In, Sign Up

Weight Loss & Diet Plans

Font Size

How the FTO Obesity Gene Works

Hint: It's More About the Calories You Take In Than Those You Burn
WebMD Health News
Reviewed by Louise Chang, MD

Dec. 10, 2008 -- A so-called obesity gene may have more to do with food choices than with metabolism or physical activity.

Researchers report that news in the Dec. 11 edition of The New England Journal of Medicine.

The gene they studied is called the FTO gene. A particular variation of the FTO gene has been linked to obesity.

That doesn't mean that people with the FTO gene variation are destined for obesity, or that other genes aren't also involved. Still, the FTO variant has attracted attention for its ties to obesity.

The new study confirms that connection and goes one step further to ask how the FTO gene influences obesity -- does it ramp up calorie consumption or dim calorie burning?

To find out, the researchers -- who included Joanne Cecil, PhD, of Scotland's University of Dundee -- studied some 2,700 elementary school kids in Scotland.

Cecil's team measured the children's height, weight, and waist and hip circumferences. They also checked the kids' FTO genes, based on saliva samples the students provided.

As expected, the heavier children were more likely to have the FTO gene variant. Their extra weight came from fat mass, not lean tissue.

The groundbreaking part of the study involved a subgroup of 76 students who got their metabolism monitored for 10 days and ate special test meals at the school. The researchers weighed the available food before and after those meals to see how much the kids had eaten.

Those tests showed the FTO variant didn't make for a sluggish metabolism, but it was linked to eating more food, especially high-calorie food, in the test meals.

So the FTO variant seemed to be involved in consumption of calories, not how the body handles those calories, note Cecil and colleagues.

For now, there's no need for a gene test to check for the FTO variant, according to an editorial published with the study. Lifestyle plays "an important role ... in enabling or restricting such susceptibility," writes editorialist Rudolph Leibel, MD, of the molecular genetics division and the Naomi Berrie Diabetes Center at Columbia University in New York.

Today on WebMD

feet on scale
Woman looking at reflection in mirror
Hot cup of coffee
butter curl on knife
eating out healthy
Smiling woman, red hair
6-Week Challenges
Want to know more?
Build a Fitter Family Challenge – Get your crew motivated to move.
Feed Your Family Better Challenge - Tips and tricks to healthy up your diet.
Sleep Better Challenge - Snooze clues for the whole family.
I have read and agreed to WebMD's Privacy Policy.
Enter cell phone number
- -
Entering your cell phone number and pressing submit indicates you agree to receive text messages from WebMD related to this challenge. WebMD is utilizing a 3rd party vendor, CellTrust, to provide the messages. You can opt out at any time.
Standard text rates apply
What Girls Need To Know About Eating Disorders
teen squeezing into jeans
fitfor Teens