3
Brown fat may
also ward off dia-
betes. According
to a study in Cell Me-
tabolism, individuals
with higher amounts of
brown fat had smaller
fluctuations in blood
sugar and thus a re-
duced risk of develop-
ing diabetes.4
Infants have
high levels of
brown fat, which
helps regulate their
body temperature.
Sadly, we lose it as we
age, and adults have
only small amounts.5
Adults can rev
up brown fat by
exposing them-
selves to cold tempera-
tures. In a recent study,
people who slept in
a mildly cold room
(about 66 degrees F)
increased the amount
and activity of their
brown fat by up to
40 percent. Sleeping
in mild warmth
(81 degrees F), how-
ever, decreased their
amount of brown fat.
Cold showers don’t
seem to affect it.6
Another brown
fat booster: apple
peels. Ursolic
acid, a substance that is
found in high concen-
trations in apple peels,
increases brown fat.
Other foods that contain
ursolic acid include
cranberries, blueberries,
plums, and prunes.7
Brown fat does
have its drawbacks.
Radiologists don’t
like it, because the heat
it generates makes it
harder for body scans
to detect tumor-related
activity in cancer pa-
tients. Although there’s
no firm evidence that
any specific foods or
nutrients can activate
brown fat, radiologists
routinely recommend
that patients eat a
high-fat, low-carb diet
before scans on the
grounds that this re-
duces brown fat activa-
tion. (This suggests that
a low-fat, high-carb
diet could boost brown
fat activity.) Radiolo-
gists even keep their
waiting rooms warm
to avoid activating
brown fat.8
Just as brown fat
isn’t perfect, nei-
ther is white fat all
bad. Even though peo-
ple tend to demonize
it, white fat delivers im-
portant health benefits.
It cushions and pro-
tects our vital organs.
It helps keep us warm.
And, of course, it stores
calories for later use,
keeping us from starv-
ing when food is scarce.9
White fat can
sometimes be
turned into
brown—it’s then called
beige or brite (“brown
in white”) fat. Like
brown fat, beige fat
burns calories and
can thus help combat
obesity. Scientists are
still trying to figure
out how the conversion
happens; one study
points to a hormone
called irisin, which
our muscles produce
when we exercise.10
Fat cells’
sensitivity to
temperature
changes means there’s
more than one way we
can get rid of unwantedrd.com 33