Nightly News   |  May 09, 2013

No interest in the gym? It may be genetic

Geneticist Molly Bray, who has isolated millions of DNA samples from thousands of subjects, found that people with one type of FTO sequence are more likely to keep exercising while those with a different type of sequence are more likely to give up. NBC’s Dr. Nancy Snyderman reports.

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This content comes from Closed Captioning that was broadcast along with this program.

>>> with two-thirds of americans either officially obese or over weight , weight loss is a struggle for millions. it turns out there may be a genetic reason for that. what some lightly call the couch potato gene. our chief medical editor dr. nancy snyderman has our report.

>> reporter: ariella jackson has a love-hate relationship with exercise.

>> i don't want to get up. i don't want to exercise.

>> reporter: when she stopped training she gained weight. the 21-year-old blames herself. but a new study indicates it could be another culprit. the gene fto, already linked to obesity risk is now linked to something else -- the will to exercise.

>> so the robot is pulling dna from this plate.

>> reporter: for a decade general 'tis dr. molly bray has isolated millions of dna samples from thousands of subjects.

>> when people tell you, exercise is hard, it hurts for me, they are not lazy. they're reporting to you exactly what they are feeling.

>> reporter: in their dna she found the person with this fto sequence is more likely to keep exercising. with this sequence, more likely to drop out.

>> good job.

>> reporter: during final trials at the university of alabama at birmingham subjects are asked to train for 15 weeks and are measured, tested, and interviewed.

>> the hardest part was just actually deciding to do it.

>> reporter: dr. bray says that is fto talking.

>> do you think physicians are going to embrace the idea of genetics and obesity?

>> well, certainly for early onset severe obesity genetics will be very helpful. it will help physicians be more understanding and less biased toward obese patients.

>> reporter: the study also found.

>> it is empowering. they no longer feel i'm weak. they say, i do have a challenge. so i'm going to do something about it.

>> reporter: it worked for shane day.

>> i couldn't run a solid mile. couldn't run a solid quarter mile . now i can run six miles.

>> reporter: proof you can fight and conquer your genes. dr. nancy snydermannbc news, birmingh birmingham, alabama.