Is there a revolution going on in how we understand fats and health? Fat is bad for us—isn’t that what we’ve been told? But butter sales are at a 40-year high, coconut oil is promoted for health and whole-fat organic milk is shown to have more Omega-3 fatty acids than the conventional skim variety. The very theory that saturated “bad” fats raise blood cholesterol and increase heart disease risk is under attack. Is everything we’ve learned about fats wrong?
Not quite. Certainly, new nutrition research is always being done. And what researchers are discovering is that not all saturated fats are the same, for example.
Saturated fats are a class of fats in which the carbon atoms are “saturated” with hydrogen atoms. No food is entirely saturated, although coconut oil, which is 92 percent saturated, comes pretty close. As a class, saturated fats tend to raise “bad” LDL cholesterol in the blood, which increases the risk of heart disease.
Recent research, though, has revealed that different saturated fatty acids have different effects on health. Stearic acid, technically a saturated fat, doesn’t raise blood cholesterol levels; dark chocolate is rich in stearic acid. Other saturated acids, such as palmitic and myristic, do raise LDL cholesterol levels substantially and are bad for the heart.
Some researchers have also suggested that replacing saturated fat doesn’t reduce heart disease risk. But that’s misleading. Replacing saturated fat with “fat free” products (many of which contain refined flour and sugar) is unhealthy. In the last 30 years, our saturated fat intake has stayed the same, but carbohydrate consumption (and calories) has increased dramatically. But it’s a healthier equation when you replace butter with olive oil, or eat omega-3-rich salmon instead of saturated-fat-laden cheeseburgers.
Red meat and high-fat dairy foods contain large amounts of “bad” saturated fats. “There are differences in saturated fatty acids,” says Tufts University Professor of Medicine Alice Lichtenstein, D. Sc., “but when we eat food, we eat a mixture. Individuals who consume more unsaturated fats versus saturated fats have better health outcomes. That means more liquid vegetable oils rather than animal fats.”
In general, says Dr. Lichtenstein, consume a moderate amount of total fat, about 25 to 35 percent of calories. If you're eating 2,000 calories a day, that's 65 grams of fat or less.
• Cooking oils:
Good or bad? It depends
Olive oil, canola oil, soybean oil, and sesame oil are all unsaturated. (Make sure soybean oil is not partially hydrogenated.) Olive oil is mostly monounsaturated and contains many healthy antioxidant compounds, while canola oil contains some plant-based omega-3 oils. “I use olive oil, soybean oil, and sesame oil, depending on what I’m cooking,” says Dr. Lichtenstein. “My personal recommendation is to favor unsaturated fatty acids and not get too caught up with whether they are polyunsaturated or monounsaturated."
• Trans fats
Good or Bad? Bad
You should not be eating anything with trans fats (found in partially hydrogenated vegetable oils.) Trans fats raise bad "LDL" cholesterol and lower good "HDL" cholesterol. They are found in some packaged foods such as cookies and crackers. Since 2006, when labeling went into effect, trans fats have been removed from many products — a process that will accelerate now that the FDA is planning to remove these artificial oils from the food supply.
• Red meat and dairy
Good or Bad? In terms of fat, bad
Dairy fat, as well as the fat in beef and pork, are the primary sources of saturated fats in the U.S. diet. Top two? Cheese and pizza. Sausage, bacon, ribs, and burgers are other big sources.
• Milk from pasture-fed cows
Good or Bad? Not great
Milk from cattle allowed to graze on pasture grass is higher in heart-healthy omega-3 fatty acids, and that’s likely true for beef and other land mammals. “The fatty acid of milk and beef is affected by what animals are fed,” says Dr. Lichtenstein. But keep your perspective. Extra omega-3s are great, but that’s no excuse to start loading up on whole milk and fatty meats. A better approach to getting your omega-3s? “Eat two fish meals a week, preferably fatty fish, but excluding deep-fat-fried fish,” says Dr. Lichtenstein. Fatty fish like salmon, sardines, and arctic char have high levels of omega-3s. Plant sources of alpha-linolenic acid, a form of omega-3 fatty acids, include soybean and canola oil, flax, flaxseeds, and walnuts, Dr. Lichtenstein adds.
Good or Bad? Mostly good
They’re high in dietary cholesterol, but that’s not such a no-no these days. “There’s less emphasis on dietary cholesterol and more on saturated fats these days,” says Dr. Lichtenstein. Recent research has found that in healthy people, eating an egg a day had no effect on heart disease risk. For people with diabetes, it may be wise to restrict egg consumption to no more than three yolks a week.
• Dark chocolate
Good or bad? Good
The stearic acid doesn’t raise cholesterol, while the antioxidants are good for heart health. Go for it, in moderation.
• Coconut oil
Good or Bad? In terms of fat, bad
It raises LDL cholesterol. Enough said; skip it. The Cleveland Clinic has a fun infographic on olive oil versus coconut oil in terms of health. (Spoiler alert: Olive oil wins.)
• Nuts, avocados, seeds
Good or Bad? Good
All good sources of unsaturated fats.
It wasn’t long ago that public health authorities told us to cut total fat. That advice is gone. Now there’s more emphasis on a plant-based diet such as the Mediterranean diet that emphasizes minimizing saturated and trans fats and replacing them with heart-healthy unsaturated fats. “Think long-term, not short-term, and in terms of dietary patterns, not individual foods and fats,” suggests Dr. Lichtenstein. “Consume a diet rich in vegetables, fruits, whole grains, legumes and beans, low in high-fat dairy, with ideally two fish meals a week. If you eat meat, keep it lean and portions small.”
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