Making sense of dietary fat
A walk down the grocery aisle will confirm our obsession
with low-fat foods. We’re bombarded with supposedly guilt-free options: baked
potato chips, fat-free ice cream, low-fat candies, cookies, and cakes. But
while our low-fat options have exploded, so have obesity rates. Clearly,
low-fat foods and diets haven’t delivered on their trim, healthy promises.
Despite what you may have been told, fat isn’t always the
bad guy in the waistline wars. Bad fats, such as trans fats and saturated fats,
are guilty of the unhealthy things all fats have been blamed for—weight
gain, clogged arteries, and so forth. But good fats such as the monounsaturated
fats, polyunsaturated fats, and omega-3s have the opposite effect. In fact,
healthy fats play a huge role in helping you manage your moods, stay on top of
your mental game, fight fatigue, and even control your weight.
The answer isn’t cutting out the fat—it’s learning to make
healthy choices and to replace bad fats with good ones that promote health and
well-being.
Myths and facts about fats
Myth: All fats are equal—and equally bad for you.
Fact: Trans fats and saturated fats are bad for you
because they raise your cholesterol and increase your risk for heart disease.
But monounsaturated fats and polyunsaturated fats are good for you, lowering
cholesterol and reducing your risk of heart disease.
Myth: Lowering the amount of fat you eat is what matters
the most.
Fact: The mix of fats that you eat, rather than the
total amount in your diet, is what matters most when it comes to your
cholesterol and health. The key is to eat more good fats and less bad fats.
Myth: Fat-free means healthy.
Fact: A “fat-free” label doesn’t mean you can eat all
you want without consequences to your waistline. Many fat-free foods are high
in sugar, refined carbohydrates, and calories.
Myth: Eating a low-fat diet is the key to weight loss.
Fact: The obesity rates for Americans have doubled in
the last 20 years, coinciding with the low-fat revolution. Cutting calories is
the key to weight loss, and since fats are filling, they can help curb
overeating.
Myth: All body fat is the same.
Fact: Where you carry your fat matters. The health
risks are greater if you tend to carry your weight around your abdomen, as
opposed to your hips and thighs. A lot of belly fat is stored deep below the
skin surrounding the abdominal organs and liver, and is closely linked to
insulin resistance and diabetes.
To understand good and bad fats, you need to know the names
of the players and some information about them. There are four major types of
fats:
- monounsaturated fats (good fats)
- polyunsaturated fats (good fats)
- trans fats (bad fats)
- saturated fats (bad fats)
Monounsaturated fats and polyunsaturated fats are
known as the “good fats” because they are good for your heart, your
cholesterol, and your overall health.
GOOD FATS
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Monounsaturated fat
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Polyunsaturated fat
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Saturated fats and trans fats are known as the “bad
fats” because they increase your risk of disease and elevate cholesterol.
Appearance-wise, saturated fats and trans fats tend to be
solid at room temperature (think of butter or traditional stick margarine),
while monounsaturated and polyunsaturated fats tend to be liquid (think of
olive or corn oil).
BAD FATS
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Saturated fat
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Trans fat
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The controversy surrounding saturated fat
For decades, doctors, nutritionists and health authorities
have told us that a diet high in saturated fats raises blood cholesterol levels
and increases the risk of heart disease and stroke. However, recent studies
have made headlines by casting doubt on those claims, concluding that people
who eat lots of saturated fat do not experience more cardiovascular disease
than those who eat less.
So does that mean it’s OK to eat saturated fat now?
No. What these studies highlighted is that when cutting down
on saturated fats in your diet, it’s important to replace them with the right
foods. For example, swapping animal fats for vegetable oils—such as replacing
butter with olive oil—can help to lower cholesterol and reduce your risk for disease.
However, swapping animal fats for refined carbohydrates, such as replacing your
breakfast bacon with a bagel or pastry, won’t have the same benefits. That’s
because eating refined carbohydrates or sugary foods can also have a negative
effect on cholesterol levels and your risk for heart disease.
In short, nothing has changed. Reducing your intake of
saturated fats can still improve your cardiovascular health—as long as you take
care to replace it with good fat rather than refined carbs. In other words, don’t
go no fat, go good fat.
If you are concerned about your weight or heart health,
rather than avoiding fat in your diet, try replacing trans fats and saturated
fats with good fats. This might mean replacing fried chicken with fresh fish,
swapping some of the meat you eat with beans and legumes, or using olive oil
rather than butter.
- Try to eliminate trans fats from your diet. Check food labels for trans fats. Avoiding commercially-baked goods goes a long way. Also limit fast food.
- Limit your intake of saturated fats by cutting back on red meat and full-fat dairy foods. Try replacing red meat with beans, nuts, poultry, and fish whenever possible, and switching from whole milk and other full-fat dairy foods to lower fat versions.
- Eat omega-3 fats every day. Good sources include fish, walnuts, ground flax seeds, flaxseed oil, canola oil, and soybean oil.
How much fat is too much?
How much fat is too much depends on your lifestyle, your
weight, your age, and most importantly the state of your health. The USDA
recommends that the average individual:
- Keep total fat intake to 20-35% of calories
- Limit saturated fats to less than 10% of your calories (200 calories for a 2000 calorie diet)
- Limit trans fats to 1% of calories (2 grams per day for a 2000 calorie diet)
Get your personalized daily fat limits
See Resources and References section below for an
easy-to-use tool from the American Heart Association that calculates your
personalized daily calorie needs, recommended range for total fats, and limits
for trans fats and saturated fats.
When focusing on healthy fats, a good place to start is
eliminating your consumption of trans fats. A trans fat is a normal fat
molecule that has been twisted and deformed during a process called hydrogenation. During
this process, liquid vegetable oil is heated and combined with hydrogen gas.
Partially hydrogenating vegetable oils makes them more stable and less likely
to spoil, which is very good for food manufacturers—and very bad for you.
No amount of trans fats is healthy. Trans fats contribute to
major health problems, from heart disease to cancer.
Sources of trans fats
Many people think of margarine when they picture trans fats,
and it’s true that some margarines are loaded with them. However, the primary
source of trans fats in the Western diet comes from commercially prepared baked
goods and snack foods:
- Baked goods – cookies, crackers, cakes, muffins, pie crusts, pizza dough, and some breads like hamburger buns
- Fried foods – doughnuts, French fries, fried chicken, chicken nuggets, and hard taco shells
- Snack foods – potato, corn, and tortilla chips; candy; packaged or microwave popcorn
- Solid fats – stick margarine and semi-solid vegetable shortening
- Pre-mixed products – cake mix, pancake mix, and chocolate drink mix
Be a trans fat detective
- When shopping, read the labels and watch out for “partially hydrogenated oil” in the ingredients. Even if the food claims to be trans fat-free, this ingredient makes it suspect.
- With margarine, choose the soft-tub versions, and make sure the product has zero grams of trans fat and no partially hydrogenated oils.
- When eating out, put fried foods, biscuits, and other baked goods on your “skip” list. Avoid these products unless you know that the restaurant has eliminated trans fat.
- Avoid fast food. Most states have no labeling regulations for fast food, and it can even be advertised as cholesterol-free when cooked in vegetable oil.
- When eating out, ask your server or counter person what type of oil your food will be cooked in. If it’s partially hydrogenated oil, run the other way or ask if your food can be prepared using olive oil, which most restaurants have in stock.
Saturated fats are mainly found in animal products such as
red meat and whole milk dairy products. Poultry and fish also contain saturated
fat, but less than red meat.
Simple ways to reduce saturated fat
- Eat less red meat (beef, pork, or lamb) and more fish and chicken
- Go for lean cuts of meat, and stick to white meat, which has less saturated fat.
- Bake, broil, or grill instead of frying.
- Remove the skin from chicken and trim as much fat off of meat as possible before cooking.
- Avoid breaded meats and vegetables and deep-fried foods.
- Choose low-fat milk and lower-fat cheeses like mozzarella whenever possible; enjoy full-fat dairy in moderation.
- Use liquid vegetable oils such as olive oil or canola oil instead of lard, shortening, or butter.
- Avoid cream and cheese sauces, or have them served on the side.
Sources of Saturated Fats
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Healthier Options
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Butter
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Olive oil
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Cheese
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Low-fat or reduced-fat cheese
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Red meat
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White meat chicken or turkey
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Cream
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Low-fat milk or fat-free creamer
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Eggs
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Egg whites, an egg substitute (e.g. Eggbeaters), or tofu
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Ice cream
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Frozen yogurt or reduced fat ice cream
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Whole milk
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Skim or 1% milk
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Sour cream
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Plain, non-fat yogurt
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Okay, so you realize you need to avoid saturated fat and
trans fat… but how do you get the healthy monounsaturated and polyunsaturated
fats everyone keeps talking about?
The best sources of healthy monounsaturated and
polyunsaturated fats are vegetable oils, nuts, seeds, and fish.
- Cook with olive oil. Use olive oil for stovetop cooking, rather than butter, stick margarine, or lard. For baking, try canola or vegetable oil.
- Eat more avocados. Try them in sandwiches or salads or make guacamole. Along with being loaded with heart and brain-healthy fats, they make for a filling and satisfying meal.
- Reach for the nuts. You can also add nuts to vegetable dishes or use them instead of breadcrumbs on chicken or fish.
- Snack on olives. Olives are high in healthy monounsaturated fats. But unlike most other high-fat foods, they make for a low-calorie snack when eaten on their own. Try them plain or make a tapenade for dipping.
- Dress your own salad. Commercial salad dressings are often high in saturated fat or made with damaged trans fat oils. Create your own healthy dressings with high-quality, cold-pressed olive oil, flaxseed oil, or sesame oil.
Damaged fat: When good fats go bad
A good fat can become bad if heat, light, or oxygen damages
it. Polyunsaturated fats are the most fragile. Oils that are high in
polyunsaturated fats (such as flaxseed oil) must be
refrigerated and kept in an opaque container. Cooking with these oils also
damages the fats. Never use oils, seeds, or nuts after they begin to smell or
taste rank or bitter.
Omega-3 fatty acids are a type of polyunsaturated fat. While
all types of monounsaturated and polyunsaturated fats are good for you, omega-3
fats are proving to be especially beneficial.
We’re still learning about the many benefits of omega-3
fatty acids, but research has shown that they can:
- Prevent and reduce the symptoms of depression
- Protect against memory loss and dementia
- Reduce the risk of heart disease, stroke, and cancer
- Ease arthritis, joint pain, and inflammatory skin conditions
- Support a healthy pregnancy
Omega-3 fatty acids and mental health
Omega-3 fatty acids are highly concentrated in the brain.
Research indicates that they play a vital role in cognitive function (memory,
problem-solving abilities, etc.) as well as emotional health.
Getting more omega-3 fatty acids in your diet can help you
battle fatigue, sharpen your memory, and balance your mood. Studies have shown
that omega-3s can be helpful in the treatment of depression, attention
deficit/hyperactivity disorder (ADHD), and bipolar disorder.
There are several different types of omega-3 fatty acids:
- EPA and DHA – Eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) have the most research to back up their health benefits. Both are found in abundance in cold-water fatty fish.
- ALA – Alpha-linolenic acid (ALA) comes from plants. Studies suggest that it’s a less potent form of omega-3 than EPA and DHA. The best sources include flaxseed, walnuts, and canola oil.
Fish: The best food source of omega-3 fatty acids
Omega-3 fats are a type of essential fatty acid, meaning
they are essential to health, but your body can’t make them. You can only get
omega-3 fats from food.
The best sources are fatty fish such as salmon (especially
wild-caught king and sockeye), herring, mackerel, anchovies, or sardines, or
high-quality cold-water fish oil supplements. Canned albacore tuna and lake
trout can also be good sources, depending on how the fish were raised and
processed.
If you’re a vegetarian or you don’t like fish, you can still
get your omega-3 fix by eating algae (which is high in DHA) or taking a fish
oil or algae supplement.
What to do about mercury in fish
Fish is an excellent source of protein, and its healthy oils
protect against cardiovascular disease. However, nearly all fish and shellfish
contain traces of mercury, a toxic metal, and some seafood contains other
pollutants known as POPs. As small fish are eaten by larger fish up the food
chain, concentrations of mercury and POPs increase, so that large, predatory
deep-ocean fish tend to contain the highest levels. That makes it best to avoid
eating these large fish, such as shark, swordfish, tilefish, and king mackerel.
Because a diet rich in seafood protects the heart and
benefits neurological development, fish remains an important component of a
healthy diet.
Recommendation: Most adults can safely eat about 12
ounces (two 6-ounce servings) of a variety of cooked seafood a week as long as
they avoid the large predatory ocean fish mentioned above and pay attention to
local sea- food advisories.
For women who are pregnant or may become pregnant, nursing
mothers, and children ages 12 and younger, caution is needed to avoid potential
harm to a fetus’s or a young child’s developing nervous system. The same
amount, 12 ounces, is considered safe with these additional guidelines:
- Eat up to 12 ounces (two average meals) a week of a variety of fish and shellfish that are lower in mercury. Five of the most commonly eaten fish that are low in mercury are shrimp, canned light tuna, salmon, pollock, and catfish.
- Another commonly eaten fish, albacore (“white”) tuna, has more mercury than canned light tuna. So, when choosing your fish and shellfish, eat no more than 6 ounces (one average meal) of albacore tuna per week.
- Check local advisories about the safety of fish caught by family and friends in your local lakes, rivers, and coastal areas. If no advice is available, eat up to 6 ounces (one average meal) per week of fish from local waters, but don’t consume any other fish during that week.
- Follow these same recommendations when feeding fish and shellfish to your young child, but serve smaller portions.
Adapted with permission from Healthy Eating: A Guide to the New Nutrition, a
special health report published by Harvard Health Publications.
Choosing the best omega-3 supplement
With so many omega-3 and fish oil supplements and fortified
foods, making the right choice can be tricky. These guidelines can help.
- Avoid products that don’t list the source of their omega-3s. Does the package list the source of omega-3 fatty acids? If not, chances are it’s ALA (sometimes from plain old canola or soybean oil), which most Westerners already get plenty of.
- Don’t fall for fortified foods. Many fortified foods (such as margarine, eggs, and milk) claim to be high in omega-3 fatty acids, but often, the real amount of omega-3 is miniscule.
- Look for the total amount of EPA and DHA on the label. The bottle may say 1,000 milligrams of fish oil, but it’s the amount of omega-3 that matters. Read the small print. It may show only 300 mg of EPA and DHA (sometimes listed as “omega-3 fatty acids”), which means you’d have to take three capsules to get close to 1,000 milligrams of omega-3.
- Choose supplements that are mercury-free, pharmaceutical grade and molecularly distilled. Make sure the supplement contains both DHA and EPA. They may be hard to find, but supplements with higher concentrations of EPA are better.
Fish oil supplements can cause stomach upset and belching,
especially when you first start taking them. To reduce these side effects, take
them with food. You may also want to start with a low dose and gradually
increase it, or divide the dose among your three meals.
How much omega-3 do I need?
The American Heart Association recommends consuming 1–3
grams per day of EPA and DHA (1 gram = 1,000 milligrams). For the treatment of
mental health issues, including depression and ADHD, look for supplements that are
high in EPA, which has been shown to elevate and stabilize mood. Aim for at
least 1,000 milligrams of omega-3 fatty acids per day.
Cholesterol is a fatty, wax-like substance that your body
needs to function properly. In and of itself, cholesterol isn’t bad. But when
you get too much of it, it can have a negative impact on your health.
Cholesterol comes from two sources: your body and food. Your
body (specifically, the liver) produces some of the cholesterol you need
naturally. But you also get cholesterol directly from any animal products you
eat, such as eggs, meat, and dairy. Together, these two sources contribute to
your blood cholesterol level.
Good vs. bad cholesterol
As with dietary fat, there are good and bad types of
cholesterol. HDL cholesterol is the "good" kind of cholesterol found
in your blood. LDL cholesterol is the "bad” kind. The key is to keep LDL
levels low while, conversely, low HDL can be a marker for increased
cardiovascular risk. High levels of HDL cholesterol may help protect against
heart disease and stroke, while high levels of LDL cholesterol can clog
arteries, increasing your risk.
Research shows that there is only a weak link between the
amount of cholesterol you eat and your blood cholesterol levels. The biggest
influence on your total and LDL cholesterol is the type of fats you
eat—not your dietary cholesterol. So instead of counting cholesterol, simply
focus on replacing bad fats with good fats.
- Monounsaturated fats lower total and bad (LDL) cholesterol levels, while increasing good cholesterol (HDL).
- Polyunsaturated fats lower triglycerides and fight inflammation.
- Saturated fats may raise your blood cholesterol.
- Trans fats are the worst types of fat since they not only raise your bad LDL cholesterol, but also lower the good HDL cholesterol.