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 A gene known as the fat mass and obesity-associated gene, or FTO,
comes in various slightly different versions, and was the first to
be linked to obesity by genetic studies, the researchers write
October 18 in the International Journal of Obesity.
These kinds of genes interacting with an environment full of junk
food ads may make children more likely to reach for a snack when
it’s advertised on TV, even when they’re full, putting them at even
greater risk of obesity, the study team writes.
“Many people ask me why they can’t walk past a plate of brownies
sitting on a table when their best friend can,” said Dr. Diane
Gilbert-Diamond, lead study author and assistant professor of
epidemiology at Dartmouth College in Lebanon, New Hampshire.
“It’s a compelling question because it gets to the individual
differences in how people respond to food,” she told Reuters Health.
“Many people think it’s a matter of self-control, yet our research
looks at how food cues motivate consumption.”
Previous studies have shown that food advertising on television can
influence how people react to and consume food. Past research has
also shown that having a high-risk version of FTO is associated with
a 20 percent higher likelihood of being obese compared to people
with other versions of the gene.
In the current study, 172 children from the Children’s Hospital at
Dartmouth-Hitchcock, ages 9 and 10, were tested to determine their
version of the gene. Of three versions, 16 percent of kids had the
most dangerous one, 18 percent had the version associated with the
lowest obesity risk and 48 percent had a moderate-risk version.
In the whole group, 26 percent of kids were obese, and those with
the high-risk genotype were more likely to fall into this category,
according to the report.
In the experiment, all the children were served a lunch and then
randomly assigned to groups that would watch one of two versions of
a 34-minute kids’ TV show embedded with eight minutes of either food
or toy ads.
The researchers gave each group of kids snack foods - gummy candy,
cookies, chocolate and cheese puffs - to eat during the show and
measured how many calories the children consumed. They also surveyed
kids about how hungry they felt.
The kids who saw the version of the show with food ads, including
one ad for gummy candy, ate an average of 48 more calories of
gummies than the children who saw the toy ads. There was no
difference in how much kids seeing food or toy ads ate of candies
that were not advertised. Those with the high-risk version of FTO
who saw the food ads were even more likely to eat the gummies,
however.
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In terms of extra calories consumed overall, kids with the high-risk
version of the gene ate 125 more calories, compared to 59 extra
calories for kids with the medium-risk version and three fewer
calories among kids with the low-risk version.
“There have been a lot of attempts to understand what makes some
people more or less susceptible to overeating,” said Dr. Jennifer
Harris, director of marketing initiatives at the Rudd Center for
Food Policy and Obesity at the University of Connecticut in
Hartford.
“The fact that these researchers made sure everyone was full before
they started the experiment, as well as the genotyping, makes the
effects even more compelling,” said Dr. Harris, who wasn’t involved
with the study.
The U.S. food industry spends $1.79 billion on marketing foods to
children under 11 each year, according to the Federal Trade
Commission. For average cable viewers, this could mean 15 TV food
ads per day, or 5,500 per year, according to a 2010 Rudd Center
report.
“This study sets the ball rolling on an exciting avenue for
research, particularly given our expanding understanding of genetic
susceptibilities to obesity and the gains we’re making in knowledge
of reward pathways in the brain,” said Dr. Emma Boyland, a lecturer
on appetite and obesity at the University of Liverpool in the U.K.,
who was not involved in the study.
“Policy progress in the field of food marketing requires evidence of
children’s vulnerability and their need for regulatory protection,”
Dr. Boyland said by email.
“Parents should remember that even within a family, children can be
different,” Dr. Gilbert-Diamond said. “One child may not overeat,
and the other may beg for a treat when walking past the ice cream
store. Even for me as a parent, that’s hard to understand.”
SOURCE: http://go.nature.com/2fas9Sc
Int J Obes 2016.
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