Wednesday, October 8, 2014
Overindulging
in
high-calorie
snacks
is
partly
caused
by
temporary
lapses
in
a
very
specific
part
of
the
brain,
according
to
a
new
University
of
Waterloo
study.
The
study,
published
in
Psychosomatic
Medicine:
Journal
of
Biobehavioral
Medicine,
is
the
first
to
conclusively
link
reduced
activity
in
the
dorsolateral
prefrontal
cortex
with
weakened
self-control
around
tasty
but
unhealthy
snacks.
“It
has
long
been
thought
that
the
dorsolateral
prefrontal
cortex
helps
to
keep
automatic
or
knee-jerk
reactions
in
check,”
said
senior
author
Peter
Hall,
a
professor
in
Waterloo’s
Faculty
of
Health.
“We
discovered
that
when
you
temporarily
dampen
the
operation
of
this
particular
part
of
the
brain,
strongly
engrained—and
quite
universal—preferences
for
high-calorie
foods
start
to
hijack
people’s
thoughts
and
even
their
eating
patterns.”
The
prefrontal
cortex
is
known
to
be
implicated
in
the
brain’s
executive
functions,
which
allow
for
conscious
control
of
reflexive
responses
to
the
environment.
While
prior
studies
have
shown
that
boosting
activity
in
the
prefrontal
cortex
reduces
cravings
for
unhealthy
foods,
this
is
the
first
study
to
show
that
temporarily
downgrading
it
increases
craving
and
consumption
of
snack
foods.
Researchers
temporarily
reduced
activity
in
the
study
participants’
left
dorsolateral
cortex
with
magnetic
stimulation,
using
a
procedure
called
theta
burst
stimulation.
After
receiving
theta
burst
stimulation,
participants
not
only
reported
greater
food
cravings
for
calorie-dense
food,
but
ate
more
junk
food
during
a
taste
test
than
when
they
received
a
bogus
stimulation.
“This
is
the
first
study
to
demonstrate
that
taking
the
prefrontal
cortex
temporarily
offline
results
in
increased
snacking,”
said
Cassandra
Lowe,
doctoral
student
in
Waterloo’s
School
of
Public
Health
and
Health
Systems
and
lead
author
on
the
paper.
Exercise and sleep will improve brain health
The
findings
will
provide
a
theoretical
framework
to
help
shape
effective
public
health
interventions,
with
a
focus
on
preservation
of
brain
health.
“The
research
suggests
that
improving
brain
health
may
be
a
fairly
important
avenue
for
fostering
dietary
self-restraint.
Interventions
aimed
at
enhancing
or
preserving
dorsolateral
cortex
function
in
healthy
populations
may
reduce
the
likelihood
of
obesity
and
other
chronic
conditions”
said
Hall.
Engaging
in
aerobic
exercise,
avoiding
alcohol
and
getting
enough
sleep
are
proven
methods
of
maximizing
the
strength
of
the
prefrontal
cortex.
“In
the
end,
if
you
want
to
improve
your
self-control
when
it
comes
to
snacking,
structuring
your
environment
to
avoid
temptations
is
crucial;
but
beyond
this,
the
key
is
to
keep
your
brain
in
shape,
so
that
you
are
up
to
the
task
when
you
encounter
temptations.
Let’s
face
it,
they
are
everywhere,”
said
Hall.