The reason why some people find it so hard to resist finishing an entire
bag of chips or bowl of candy may lie with how their brain responds to food
rewards, leaving them more vulnerable to overeating.
In a study with children, researchers found that when certain regions of
the brain reacted more strongly to being rewarded with food than being rewarded
with money, those children were more likely to overeat, even when the child
wasn’t hungry and regardless of if they were overweight or not.
Shana Adise, a postdoctoral fellow at the University of Vermont who led the
study while earning her doctorate at Penn State, said the results give insight
into why some people may be more prone to overeating than others. The findings
may also give clues on how to help prevent obesity at a younger age.
“If we can learn more about how the brain responds to food and how that
relates to what you eat, maybe we can learn how to change those responses and
behavior,” Adise said. “This also makes children an interesting population to
work with, because if we can stop overeating and obesity at an earlier age,
that could be really beneficial.”
Previous research on how the brain’s response to food can contribute to
overeating has been mixed. Some studies have linked overeating with brains that
are more sensitive to food rewards, while others have found that being less
sensitive to receiving food rewards makes you more likely to overeat.
Additionally, other studies have shown that people who are willing to work
harder for food than other types of rewards, like money, are more likely to
overeat and gain weight over time. But the current study is the first to show
that children who have greater brain responses to food compared to money
rewards are more likely to overeat when appealing foods are available.
“We know very little about the mechanisms that contribute to overeating,”
Adise said. “The scientific community has developed theories that may explain
overeating, but whether or not they actually relate to food intake hadn’t yet
been evaluated. So we wanted to go into the lab and test whether a greater
brain response to anticipating and winning food, compared to money, was related
to overeating.”
For the study, 59 children between the ages of 7 and 11 years old made four
visits to the Penn State’s Children’s Eating Behavior Laboratory.
During the first three visits, the children were given meals designed to
measure how they eat in a variety of different situations, such as a typical
meal when they’re hungry versus snacks when they’re not hungry. How much the
children ate at each meal was determined by weighing the plates before and
after the meals.
On their fourth visit, the children had fMRI scans as they played several
rounds of a game in which they guessed if a computer-generated number would be
higher or lower than five. They were then told that if they were right, they
would win either money, candy or a book, before it was revealed if they were
correct or not.
The researchers found that when various regions of the brain reacted more
to anticipating or winning food compared to money, those children were more
likely to overeat.
“We also found that the brain’s response to food compared to money was
related to overeating regardless of how much the child weighed,” Adise said.
“Specifically, we saw that increased brain responses in areas of the brain
related to cognitive control and self control when the children received food
compared to money were associated with overeating.”
Adise added that this is important because it suggests there may be a way
to identify brain responses that can predict the development of obesity in the
future.
Kathleen Keller, associate professor of nutritional sciences, Penn State,
said the study — recently published in the journal Appetite — backs up the theory that an
increased brain response in regions of the brain related to rewards is
associated with eating more food in a variety of situations.
“We predicted that kids who had an increased response to food relative to
money would be the ones to overeat, and that’s what we ended up seeing,” Keller
said. “We specifically wanted to look at kids whose brains responded to one
type of a reward over another. So it wasn’t that they’re overly sensitive to
all rewards, but that they’re highly sensitive to food rewards.”
Keller said the findings give insight into how the brain influences eating,
which is important because it could help identify children who are at risk for
obesity or other poor eating habits before those habits actually develop.
“Until we know the root cause of overeating and other food-related
behaviors, it’s hard to give good advice on fixing those behaviors,” Keller
said. “Once patterns take over and you overeat for a long time, it becomes more
difficult to break those habits. Ideally, we’d like to prevent them from
becoming habits in the first place.”
No comments:
Post a Comment