Despite what fad diets and catchy headlines would lead you
to believe, fat is not all the same. And you need to stop treating it that way.
So if you operate by a “fat is fat and fat is bad” sort of mentality, it’s
worth taking a few minutes to get to know your fat.
Here, experts (including a fat researcher!) share what you
really need to know about fat on your frame—especially if you’re trying to
lose weight, get healthy, or live longer:
1.Essential
Fat
What It
Is: The
fat you need to live. “Essential fats help regulate body temperature, vitamin
absorption, cell structure, and hormones such as fertility hormones,” explains
Naureen Sajwani, R.D., a clinical dietitian at Weiss Memorial Hospital in
Chicago. “Essential fat is found in many parts of the body including nerve
membranes, bone marrow, and membranes protecting body organs. Essential fat is
neither subcutaneous nor visceral." (Don't worry, we’ll dive into
subcutaneous and visceral fat later on.)
What
You Need To Know If You’re Trying To Lose Weight: You
cannot lose essential fat without compromising your health—and in a big way.
For good health, women need 10 to 13 percent of their total weight to come from
this essential fat, according to the National Academy of Sports Medicine.
Unfortunately, many women often strive for and achieve even
lower body fat percentages through extreme dieting and exercising, putting
their health at risk. That’s why many female figure competitors (who cut their
body fat percentages to as low as 6 to 10 percent for competitions), often
experience extreme hormonal dips and lose their periods. J. Mark Brown,
Ph.D., a lipid (a.k.a. fat) researcher with the Cleveland Clinic Lerner
Research Institute, also notes that too-low levels may also throw off the
body’s ability to regulate blood sugar. In animal studies, mice with excessively
low levels of body fat display symptoms of prediabetes and Type 2 diabetes, he
says.
When trying to lose weight, remember to keep your health as
your top priority. (And remember that plenty of pics on Instagram feature
less-than-healthy body fat levels.) Make sure that your body fat percentage
doesn’t go below 10 to 13 percent. Many scales—and even some fitness
trackers—now come equipped to gauge your body fat.
2.White
Fat
What It
Is: The
main form of fat cell in the body, this is what most people think of when they
talk about fat. Also called “white adipocytes,” these fats cells are literally
white, thanks to a low density of mitochondria (microscopic fat-burning power
plants) and blood vessels, Brown says. The cells store fat in the form of
triglycerides, padding your energy reserves and body. “White fat is the largest
energy backup in the body, and provides cushion for our organs and external
body structure,” Sajwani says. “In addition, it produces leptin and a form of
estrogen which regulate hunger, and has receptors for hormones such a growth
hormone, cortisol, and insulin.”
What
You Need To Know If You’re Trying To Lose Weight: While
some white fat helps promote hormonal health and boosts levels of the feel-full
hormone leptin, too-high levels of white fat can contribute to “leptin
resistance.” When the body is faced with consistently high levels of leptin, as
a result of excess white fat, the body becomes less sensitive to leptin’s
effects. The result: a cycle of hunger and (white) fat gain.
Since the majority of your non-essential fat is white, you
can tell if you've got too much or too little white fat by measuring your body
fat percentage. In women, total body fat percentages of 16 to 23 are often
considered good. Levels of more than 30 are typically classified as overweight.
3.
Brown Fat
What It
Is: “The
polar opposite of white fat, brown fat burns rather than stores energy,” Brown
says. Its energy-burning capabilities and brown color are both due to the fact
that it’s packed tight with mitochondria. Those mitochondria burn fatty acids
to generate heat and help keep the body a balmy 98.6 degrees. Only proven to exist
in humans in the past decade, brown fat levels are especially high in babies.
What
You Need To Know If You’re Trying To Lose Weight: The
verdict is still out on whether or not you can convert white fat into brown
adipose tissue (BAT), but it is clear that by increasing the activity of your
body’s existing brown fat, you can boost your ability to burn calories from
white fat. Exactly how to do that is still unclear, though.
One Harvard study shows
that hanging out in an environment cooled to 60.8 degrees for 10 days straight
increases brown fat activity (although it didn’t increase actual levels of
brown fat). While it’s likely a good idea to keep your home cool, especially while
you sleep, don’t make yourself miserable. After all, researchers still
have a lot of work to do to figure out how findings such as this can best be
used to combat obesity, Brown says.
4.
Beige Fat
What It
Is: Beige
fat looks and acts like a cross between white and brown fat, but research
suggests that beige fat is its own unique cell type, rather than a midpoint on
the white-to-brown spectrum, Brown says. Fortunately, research does also
suggest that white fat can convert into beige fat. “The beige-ing of white fat
is really the holy grail in anti-obesity therapeutics,” he says. “To turn white
fat into beige fat would in theory make you leaner because you are burning fat
and releasing it as heat.”
What
You Need To Know If You’re Trying To Lose Weight: Animal
studies suggest that catecholamines, hormones released when you’re either
stressed or cold, help jumpstart the process of converting white into beige
fat, explains Brown, whose 2017 research identified
a key enzyme that regulates the beige-ing of white fat. Brown notes that one
particularly helpful stressor in the beige-ing of brown fat is believed to be
exercise. During exercise, muscle secretes specialized proteins that may help
turn your white fat beige. So get moving.
5.
Subcutaneous Fat
What It
Is: “Subcutaneous
fat is the layer of fat found right underneath our skin,” Sajwani says. “About
90 percent of fat in our body is in the form of subcutaneous fat.” A
combination of white, beige, and brown fat, and a certain amount of
subcutaneous fat is healthy. But, again, too much of the white variety can
spell trouble by throwing off hormone levels and sensitivity.
What
You Need To Know If You’re Trying To Lose Weight: The
most common method of measuring subcutaneous fat levels is a skin-fold test in
which a professional pinches your fat with calipers. It’s not exactly fun, but
it’s not painful, and many gyms and healthcare professionals are trained to
perform the tests.
In terms of lowering your levels, it’s all about calories in
versus calories out. Sajwani recommends zeroing in on your nutrition (think:
cut down on refined carbs and empty calories) while also
performing high-intensity exercise on the regular.
6.
Visceral Fat
What It
Is: What
your girlfriends might call “belly fat,” visceral fat is white fat that is
stored within the abdominal cavity around a number of organs such as the liver,
pancreas, heart, and intestines rather than right under your skin like
subcutaneous fat. “Researchers have found that visceral fat secretes a protein
called retinol-binding protein 4, which has been shown to increase resistance
to insulin, leading to glucose intolerance and Type 2 diabetes,” Sajwani says.
“High visceral fat storage has also been linked to breast cancer, colorectal
cancer, stroke, Alzheimer's disease, and dementia.”
What
You Need To Know If You’re Trying To Lose Weight: In
the fight against fat, this is enemy No. 1. “To gauge your visceral fat level,
determine waist-to-hip ratio. First, take the circumference measurement of both
your waist and your hips at their largest point. Next, divide your waist
measurement by your hip measurement. If the ratio is higher than 1.0 for men
and 0.85 for women, then the amount of fat is considered excessive,” Sajwani
says. Alternatively, you can just measure the circumference of your waist,
says Steven Wilson, M.D., a family medicine physician with Redlands
Community Hospital in California. “A waist circumference greater than 35 inches
for a woman is considered abnormal and consistent with increase visceral body
fat,” he says.
While visceral fat responds to the rules of caloric balance,
just like subcutaneous fat does, research shows that it’s particularly
sensitive to the inflammatory effects of processed foods, Wilson says.
Meanwhile, evidence shows that a diet rich in unrefined foods, protein,
unsaturated fatty acids, whole grains, and fiber can significantly reduce
visceral fat levels. As can getting the recommended seven to nine hours of
sleep per night. And one 2015 study found
that strength training is more effective at preventing age-related increases in
belly fat compared to cardio.
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