The less fat you eat the better— right? Not necessarily.
Although fat was once the very face of dietary evil, recently it’s gotten major facelift of sorts. It’s no wonder e equate “fat” with “bad”. A half century ago, scientists made a discovery that made us think hard, almost for the first time, about our food and health: People who live in counties where the diets are rich in saturated fat have more heart attacks than people who eat less meat, dairy foods, and other source of the stuff. Later research showed that eating saturated fats raises blood levels of cholesterol, causing this waxy substance to build up in the arteries and block blood flow to the heart.
Fats eventually became nutrition enemy number one. Remember the old USDA Food Guide Pyramid? Fats and oils (which are simply liquid fat) were lumped together with sweets in the tiny uppermost wedge of the pyramid, accompanied by the stern recommendation: USE SPARINGLY. Cookbooks loaded with fat-free recipes filled bookstore shelves. “Nonfat!” and “Fat-free!” were stamped on food labels, often on products that never contained fat in the first place. Doctors turned-author, such as Dean Ornish, M.D., preached the virtues of very low fat diets.
These messages may have convinced you to make some very good, important changes, such as switching from whole milk to fat-free and stripping bacon from your diet. But they also had led consumers to make some unfortunate choices, and we’re not just talking about those tofu dogs you brought a few years back. One consequence of the anti-fat movement was that many people cut back on all fats—a trend to may have actually made us sicker, according to some prominent experts.
Your body stores about 85% of the fat you eat. Ideally, you break down most of this stored energy by staying physically active. If not, the fat you eat becomes the fat you are afraid of, the kind that makes your clothes too tight and compromise your health.
However, about 20% of the fat in your food is not reserved for later use. Instead, your body puts it right to work, since a surprising variety of tissues and biological processes need a daily mixture of fat. Without fat, your hair and skin would be dull, brittle, and dry. More importantly, fat that you consume allows your body to absorb the so-called fat-soluble vitamins, including A, D, E, and K. All of the cells in your body needs fat to build a healthy protective membrane. Fats also supply the raw materials that your body utilizes to make chemicals that regulate blood pressure, prevent blood clots, and regulate the body’s response to injury and infection. In fact, the stuff that gives many foods that familiar exquisite texture is so important to human health that scientists in the 1920s briefly called certain forms of fat “vitamin F.”
If you desire fudge of filet mignon with béarnaise sauce, blame evolution. Our ancestors grew a taste for fats as a way to be sure packing on extra pounds to survive in time when food was very little. A gram of fat has twice as many calories as an equal amount of carbohydrate or protein. No wonder survival food rations are often packed with fat.
Off course, few of us need extra calories today. And it’s still as important as ever to cut back on saturated fat—think beef, butter, and cheese—a major culprit behind heart attacks, not to mention insulin resistance, the problem at the core of diabetes. But cutting out all of the fat in your diet might not pay off as you’d expect. That’s because experts have discovered that far from being deadly, daily doses of certain fats actually fights disease. Many scientists and nutrition experts now believe that these unsaturated fats—a.k.a. the “good” fats—inhibit everything from diabetes, depression, and dementia to cancer, joint pain, and yes, even heart disease.
Replacing some of the calories in your diet that come from saturated fats with calories from unsaturated fats (trading a hamburger for a salmon burger, for instance) may be even better for you than replacing them with carbohydrate calories. Studies show that swapping saturated fat in your diet for carbohydrate-rich foods, such as rice or pastas, has only a modest effect on heart disease risk. On the other hand, Harvard researchers studied the diets of 80,000 nurses for 14 years and determined that replacing just 5 percent of calories from saturated fat with an equal amount of good fat can reduce the risk of heart disease by 42 percent.
It’s not just your heart that benefits from these fats though. They also fight an impressive range of other diseases, as you’ll read. But first let’s explain which fats we’re talking about.
Defining good fats
As anyone who has ever struggled to lose weight knows, the body is very good at making it own fat, which it stores most prominently on the hips, thighs, and midsection. That’s because even if you eat nothing but rice cakes and carrot sticks, but you eat too many of them, your body converts the sugars in those foods that it doesn’t burn for energy into triglycerides, the storage form of fat.
However, your body can’t make some type of fatty acids—the building blocks of fat—that are necessary for optimal health. That’s why your diet need to include the aptly named essential fatty acids, which come mainly from fish and plant oil and fall into the broader category of polyunsaturated fats. Meanwhile, monounsaturated fats must also be included in your diet, which form the other major category of unsaturated fat—but mounting research suggest that you may not live as long or as well as people who do enjoy plenty of these other good fats.
Monounsaturated fats: Olive oil and beyond
You may have been surprised to learn a few years back that a bit player in your cupboard was in fact a nutritional marvel. Scientific trials, such as the Lyon Diet Heart Study, found that eating a so-called Mediterranean diet appears to protect the cardiovascular system more efficiently than a typical low-fat diet. The cornerstone of a traditional Mediterranean diet? It’s olive oil, one of nature’s richest sources of monounsaturated fat.
In fairness, some of the wonders of the olive oil may have been overhyped by the cooking oil industry. After all, the traditional Mediterranean diet also includes frequent servings of fruits and vegetables as well as plenty of fish. But it’s hard to ignore the fact that people in the Lyon Diet Heart Study who ate a Mediterranean-type diet consume plenty of fat, much of it in the form of monounsaturated fatty acids in olive oil, yet they had four times fewer heart attacks than people asked to eat a standard low-fat diet.
Olive oil isn’t the only good source of monounsaturated fat that may already be in your kitchen. Its shelf mate, canola oil, is another. Nuts are packed with monos, too, so add peanut butter and peanut oil to the list. Need an excuse to eat avocado? The green flesh of these nubby-skinned fruits contains nearly as many grams of fat as a Big Mac, but the fat is mostly monounsaturated.
Polyunsaturated fats: Go fish, go nuts
Remember the cod-liver oil of your grandparent’s days? It used to be fashionable to joke about this favorite all-purpose remedy. But who’s laughing now? Fish oil is the best source of omega-3 fatty acids, one of the two main types of polyunsaturated fat and probably the best-for-you-fat around. In recent years, scientists have linked a boatload of new health benefits to consuming this form of fat, such as lower rates of heart disease and depression.
You don’t have to swallow cod-liver oil to get omega-3s, though. Eating seafood, especially cold-water fish, is your best option. The fat that protects all marine creatures from cold water, from artic char to Atlantic salmon, is packed with omega-3s. Unlike with beef or pork, you want to go for the fattiest fish possible, such as salmon, since more oil means more healthful omega-3s. Albacore tuna is another good choice, as are Atlantic mackerel, lake trout, herring, and sardines. (But think twice before gulping down cod-liver oil, even if you can stand the taste; the recommended doses may contain toxic levels of vitamin A and D.)
Fish-phobes, fear not: There are other ways to put these fats to work in your body. Fish-oil capsules are an option, though you should talk to your doctor before taking them because they can thin the blood. Walnuts, walnut oil, flaxseeds, and flaxseed oil won’t give you omega-3s exactly, but they do supply a type of fat called alpha-linolenic acid (ALA), which your body can turn into omega-3s.
Less famous—and perhaps less healthful—than the omega-3s are their cousins, the omega-6s, the kind of fat you get when you pour corn, sunflower, or safflower oil into your pan or eat packaged foods that contain soybean oil, which food processors use in a wide range of products. Margarines, usually made of vegetable oil, is another major source of omega-6. Most of us consume far more of these fats than omega-3s , and that may spell trouble, according to some experts.
By the way, all fats and oils contain a blend of saturated, monounsaturated, and polyunsaturated fatty acids, along with smaller amounts of other elements. But any given fat or oil tends to have a higher concentration of one type. For example, 62 percent of the fat in butter is saturated, while 29 percent is monounsaturated and a trace is the polyunsaturated variety. By contrast, just 14 percent of the fat in olive oil is saturated, while 74 percent is monounsaturated and 8 percent is polyunsaturated.