The Truth About Saturated Fats
For years you've been told that the saturated fat you eat is public enemy
No. 1 in the battle against obesity and heart disease. Turns out, it may
actually be — gasp! — good for you.
Good Fats Versus Bad Fats
I was a
card-carrying skinny-latte-drinking low-fat girl. I ordered frozen yogurt
instead of ice cream, grilled chicken instead of steak, and I snacked on
low-fat cheese and reduced-fat crackers. With a family history of high
cholesterol (my own number hovered slightly beyond the healthy range), I
figured that limiting saturated fat was smart.
But in
the past couple of years I've made some changes. Inspired by the movement to
eat locally, I started shopping at my farmers' market: I bought a quarter of a
grass-fed cow and stocked my basement freezer with the beef, which I ate once a
week. I also splurged on local bacon sometimes. When my store was out of skim
milk, I discovered I preferred creamier 1 percent. I began eating dark
chocolate daily. At the same time, I bought fewer packaged crackers, granola
bars, and other snacks.
At a
recent checkup, I was shocked: Even though I was eating foods rich in saturated
fat and a seemingly more indulgent diet, my total cholesterol was down 10
points, my "bad" LDL cholesterol was stellar, and my "good"
HDL was the highest it's ever been. And bonus: I hadn't gained any weight! How
was that possible? Actually, the health benefits I experienced may be
surprisingly common, a growing number of experts say.
What We're Told
Since the
epic fail of the fat-free craze of the '80s and '90s, we've learned a lot. The
hope was that by cutting fat from our diets, we would trim inches from our figures.
Instead, the exact opposite happened: Because fat-free cookies, cheese, chips,
and crackers were missing the critical fat that makes us feel full, we ate
double — sometimes triple — the usual portion. And because manufacturers dumped
extra sugar into these foods to make them taste better, we took in just as many
calories and often many more. "The low-fat message backfired," says
Frank Hu, MD, PhD, a professor of nutrition and epidemiology at the Harvard
School of Public Health. "It led to a proliferation of products that were
loaded with sugar, refined carbohydrates, and calories."
These
days, advice about fat has shifted away from "Eat less fat" to
"Eat the right fats." Fats are now labeled "good" and
"bad." The good guys are unsaturated fats: monounsaturateds (MUFAs),
found in foods like olive oil and avocados, and polyunsaturateds (PUFAs), found
in sunflower and corn oils, among others, and in the omega-3s in salmon and
walnuts. Both types earned gold stars because they've been shown to lower blood
cholesterol and the risk for heart disease.
The
villain, we've long been told, is saturated fat. The conventional wisdom, which
dates to the 1950s, is that saturated fat, which is present in meat, dairy, and
some plant products, increases our total cholesterol and chance for heart
disease and stroke. Trans fat, a relative newcomer that dominated packaged
goods and fast food, is another bad guy: It not only ups our LDL cholesterol
but also lowers our HDL cholesterol (the kind that helps sweep bad cholesterol
out of the body). The American Heart Association recommends limiting your
intake of saturated fat to less than 7 percent of your total calories (if you
eat 2,000 calories a day, that's 16 grams, roughly the amount in a chocolate
milk shake) and of trans fats to no more than two grams a day.
Saturated Fat Is Wrongfully Accused
After
decades of bashing saturated fat, the medical community was stunned by a 2010
study in the American Journal of Clinical Nutrition. In a research
analysis, scientists discovered that there wasn't enough proof to link
saturated fat to either heart disease or stroke. It wasn't the first time this
fat had been vindicated: Four years earlier the Women's Health Initiative study
found that eating less saturated fat didn't result in lower rates of heart
disease or stroke. The 2010 analysis, however, was so big and so thorough —
involving 21 studies and nearly 350,000 people — that it grabbed experts'
attention. "Everyone had just assumed that the evidence against saturated
fat was strong," says study author Ronald Krauss, MD, a professor of
nutritional sciences at the University of California, Berkeley, who was
surprised by the finding and the controversy it created. "We had to work
hard to get our study published. There was an intrinsic mistrust of this kind
of result."
Researchers
say there were even earlier clues that saturated fat didn't deserve its
reputation as top dietary villain. The decades-old "diet-heart
hypothesis" — the idea that saturated fat is bad for the heart — was
mostly based on animal studies and short-term trials that looked only at
people's cholesterol levels, not at whether they actually had heart attacks.
"Those studies are great for making hypotheses but not for making
widespread recommendations," says Dariush Mozaffarian, MD, an associate
professor of medicine and epidemiology at Harvard Medical School and a
researcher of diet and heart health. "When we started getting evidence
from longer trials and observations, we realized that the truth is more nuanced
than we thought."
What
researchers discovered was that cutting out saturated fat didn't make much
difference, until you considered what people ate in place of it. Swapping
animal fats for vegetable oils — for instance, using soybean oil instead of
butter — appeared to lower LDL cholesterol levels and disease risk. But trading
your a.m. bacon for a bagel didn't do the trick. "When you replace
saturated fats with refined carbs, your triglycerides can go up and your good
HDL cholesterol can go down," explains Alice H. Lichtenstein, the director
of the Cardiovascular Nutrition Laboratory at Tufts University. High
triglycerides and low HDL are risk factors for cardiovascular disease and criteria of metabolic syndrome,
a cluster of health problems linked to diabetes and heart disease.
Eating
less saturated fat doesn't seem to help your weight, either. A study in The
New England Journal of Medicine found that people on a low-carb diet shed
pounds faster and had better cholesterol levels than those on a low-fat diet,
even though the low-carb group was taking in relatively more saturated fat.
This may be because people eating fewer carbs release less insulin, which may
reduce fat storage, control hunger, and influence metabolism in a way that
helps keep cholesterol in check.
The Different Kinds of Fat
So why, despite the explosion of positive study findings, is saturated fat
still considered evil? One major factor: It's not a single fat. There are more
than two dozen kinds, and "they're not created equal," says David
Katz, MD, director of Yale University's Prevention Research Center. So it's
difficult to make a general recommendation about saturated fats as a whole. Yet
that's exactly what the Dietary Guidelines for Americans do. Here are the four
major types of saturated fats in our diet, according to the Dietary Guidelines
Advisory Committee:
(1) Palmitic and (2) myristic acids
At first glance, palmitic acid (found in palm oil, butter, and eggs) and
myristic acid (found in cheese, milk, butter, and beef) fit the bad-guy
profile. They appear to increase inflammation and LDL cholesterol. But here's
where things gets tricky: The rise in LDL is at least partly due to an increase
in the size of each LDL particle in the body, which may not be as dangerous as
an increase in the number of particles. These saturated fats also raise HDL in
the process, so the net effect may be neutral, not bad.
(3) Stearic acid
This saturated fat, present in chocolate and beef, doesn't raise LDL at all. In
fact, the Dietary Guidelines Advisory Committee stated in its scientific report
that the acid should not be considered a "cholesterol-raising"
saturated fat. (Though the committee itself continues to recommend cutting back
on saturated fat and doesn't mention stearic acid. Confused? Us too.) In fact,
this type of saturated fat is an important reason dark chocolate gets the green
light from most health experts. "The stearic acid in dark chocolate has no
negative effect on blood cholesterol," Dr. Katz says.
(4) Lauric acid
There's some indication that lauric acid may not be harmful either. It's found
in coconut oil, the latest superfood, which has been touted to do everything
from lower stress to whittle your waist. But those claims are overblown. "Lauric acid is
probably an innocuous fat," Dr. Katz says. "But no studies indicate
that coconut has any edge over other oils that we know confer a benefit, like
olive oil."
The Real Villain
Some researchers believe that saturated fat may simply be a convenient
scapegoat for the true problem with our diets: the food we eat. The top three
sources of saturated fat for Americans are cheese, pizza, and such grain-based
desserts as cookies and cakes. The foods that saturated fat is found in might
actually contribute to the risk to your health. Case in point: Two slices of
pizza with meat toppings at a popular chain not only pack 20 grams of saturated
fat but also nearly 1,000 calories, more than a day's supply of sodium and a
gram of trans fat. In a recent study that linked red meat to a higher rate of
death, processed meat, which is high in sodium and other preservatives, was
found to be especially dangerous. "We should stop focusing on just one
chemical in food and instead look at the overall package it comes in," Dr.
Krauss explains.
Modern diets are a veritable perfect storm of unhealthiness, according to
Dr. Mozaffarian. He and his colleagues analyzed the number of deaths from
various risk factors and singled out five dietary patterns to study: high in
trans fat, high in saturated fat, high in sodium, low in fruits and vegetables,
and low in omega-3 fatty acids from fish (all pretty darn common in our
superprocessed society). When they looked at deaths associated with each
pattern, diets high in saturated fat came in, well, dead last. "If you eat
a lot of salt and trans fats and few fruits, vegetables and fish, you're at a
high risk for heart disease no matter what your saturated fat intake is,"
Dr. Mozaffarian says. "Conversely, higher or lower saturated fat will have
a small effect if you're doing everything else right."
Bottom line: Saturated fat doesn't deserve its bad-guy reputation. That's
why shifting the focus to more pressing dietary problems — for example, too
many refined carbs or a dearth of produce — is critical, experts say. Read on
for eight easy ways to do just that. And pass the dark chocolate, please.
8 Rules to Eat By
So saturated fat is not the evil you thought. But what does that mean for
your diet? These eight must-dos cut through the confusion.
1. Load up on whole foods.
If you eat mostly heart-healthy, nutrient-rich produce, whole grains, nuts,
beans, and fish, then saturated fat shouldn't be a problem.
2. Don't overdo it.
Saturated fat may not be a culprit, but it doesn't offer the same health
benefits as unsaturated fat. So don't start cooking with butter or eating more
meat. Fish, beans, and lentils are still healthier protein sources than red
meat.
3. Choose low-fat dairy.
Low-fat milk and yogurt are good choices because they have fewer calories and
just as much calcium and vitamin D as full-fat versions.
4. Beware of health halos.
Local organic cream from the farmers' market is still cream, and it packs loads
of calories. Foods like ice cream and bacon should be considered splurges. And
a product labeled "No saturated fat" may be full of sodium, sugar,
and refined flour.
5. Don't go loco for coconut.
Choose liquid vegetable oils, such as canola and olive, that are a mix of MUFAs
and PUFAs. Though some people are switching to coconut oil, there's no evidence
that it's as beneficial as these oils are.
6. Steer clear of trans fats.
They're very bad for you, and they mostly appear in processed foods. Avoid
anything that has "partially hydrogenated oils," a code name for
trans fats, in the ingredients list.
7. Consider your carbs.
Get most of your carbohydrates from fruits, vegetables, and whole grains, not
from sugary and refined starches, like crackers and desserts.
8. Treat yourself to dark chocolate.
Indulge in a small piece — about one ounce — every day. The saturated fat in it
won't harm your health, and the chocolate packs flavonoids that act as
antioxidants, protecting cells from damage.
Source: http://www.fitnessmagazine.com/recipes/healthy-eating/nutrition/good-and-bad-fats/
