It's known that genetics and lifestyle influence weight.
Now, a study sheds light on the effects that family and friends can
have on weight.
Harvard Medical School researchers analyzed data collected for
more than three decades from 12,067 adults. The study, published in
New England Journal of Medicine
, showed that an adult's chances of becoming obese increase by
57% when a friend became obese, 40% when a sibling became obese,
and 37% when a spouse became obese.
The findings suggest that when someone close to you gains
weight, you may be more accepting of your own weight gain and the
two of you can influence each other's behavior.
This research has prompted much media hype suggesting that
friends can make you fat or that obesity is contagious. But the
researchers stress that this isn't the way the study should be
interpreted. Rather, they say the study showed the potential for
family and friends to influence behavior in negative
This new insight can be used to help design weight loss and
healthy lifestyle programs that use peer support and influence to
make positive changes in eating and physical activity habits.
What This Means to You
This study was conducted over more than three decades and did
not include kids and teens.
Parents should not use these findings to discourage friendships
with overweight children or justify the social stigmas they already
face. A variety of factors influence a person's weight,
including genetics and environment, like family and friends'
eating and activity habits. The new research suggests that, among
adults, social cues about what's "normal" also play a
It's common for kids, especially as they grow into teens, to
be influenced by their friends and peers. What "everyone
else" is doing can also influence their choices when it comes
to behaviors like smoking, drinking, drug use, and even what kind
of food they eat when they're together.
But just as parents can mitigate peer pressure for something
like smoking, they can also moderate the social influences that
affect kids weight.
When kids are young, parents can ground kids in healthy habits
for eating and being physically active, creating an environment
that fosters those habits, and setting good examples. If parents
enjoy eating healthy foods, sensible portions, and being active
every day, kids will be more likely to as well. That will be their
Here are ways that parents can help kids develop healthy
Promote physical activity.
Encourage kids to be active every day. Whether via team sports or
a non-competitive solo pursuit, find activities that fit their
abilities and temperaments.
Control the food-supply lines.
Stock up on healthy foods; limit those with added sugar and
fat and low nutritional value.
Limit screen time:
Limit the sedentary time that your kids spend in front of
the TV and computer and playing video games to less than 2 hours
Encourage mindful eating.
Teach your kids to heed internal signals of hunger or fullness,
and help them develop good strategies for coping with moods like
boredom and anxiety, which can often prompt mindless eating.
Nurture health from the inside out.
Encourage hobbies and friendships that nurture your kids'
self-esteem and confidence. Kids who have a strong sense of
themselves will be equipped to deal with peer pressures and
influences down the road.
Set a good example.
Eat healthy and be active every day, and show kids how much you
enjoy it and how good it makes you feel. What parents practice
has much more of an impact than what they preach!
And finally, encourage your kids to develop a diverse group of
Make it clear that you have zero tolerance for name-calling or
stereotyping of kids who are overweight or different in any other
way. Help your child develop a sense of empathy for those who stand
out. Watch your own attitudes, comments, and behavior to make sure
that you aren't subtly endorsing social stigmas or sending the
message that it's OK to dismiss or shun others just because
If parents instill healthy values and habits in kids early on,
kids will be prepared to handle and interpret whatever social
influences they encounter as they grow.
Mary L. Gavin, MD
Date reviewed: July 2007
Note: All information is for educational purposes only. For specific medical advice,
diagnoses, and treatment, consult your doctor.
© 1995-2009 The Nemours Foundation/KidsHealth. All rights reserved.