For decades, fat has been blamed for everything from heart disease to obesity to cancer. But new research shows that fat can be good for you.
Janet Paskin | June/July 2009 issue
Jenny Matthau stands in front of hundreds of students at the Natural Gourmet School and speaks heresy. The New York City culinary program specializes in “health-supportive, whole-foods cuisine” with a “plant-based curriculum.” Beef and pork aren’t on the syllabus, to say nothing of veal—and the school’s alumni run kitchens at health spas and work in restaurants with names like Organic Planet. So when Matthau, who’s president of the school and teaches the core nutrition class, delivers her lecture in praise of fat, students are often surprised.
“A lot of students expect to hear just what the government is saying: You have your good fats and your bad fats, and you should try to eat a very low-fat diet,” Matthau says. “And we don’t agree.”
Instead, Matthau’s lecture includes a long section on why we need fats of all kinds in our diets, much more than we’ve been led to believe. She points out societies like the Maasai, a Kenyan tribe that counts meat, blood and whole milk among its dietary staples, yet has low rates of heart disease and obesity. She praises fat’s capacity to add flavor to a dish and make people feel full. “Fat makes things taste great, period,” Matthau says. “I’m a big fan.” Even so, sometimes it feels like a losing battle. “Students still want alternatives to butter.”
For more than three decades, we’ve been told that fatty foods are deadly, to blame for a full menu of health hazards, from heart disease to obesity to cancer. Regularly described as the nutritional equivalent of cigarettes, fat has been the target of public-service campaigns and municipal bans aimed at keeping us slender and healthy. But a growing body of international research suggests our obsessive fear of fat may be misplaced. A high-fat diet won’t necessarily make us sick or fat; a low-fat diet may not make us healthy or slim.
Even the American Heart Association (AHA), a leader in the campaign against dietary fat, recently revised its nutritional guidelines, increasing the daily recommendations for fat. “The science just wasn’t there,” acknowledges Robert Eckel, president of the AHA and a professor of endocrinology, metabolism and diabetes at the University of Colorado Health Sciences Center.
Not only that, but our myopic aversion to fat may be doing more damage than an order of steak frites ever could. In our effort to avoid the demon lipids at all costs, we’re forever tinkering with our diets—substituting Snackwells for Oreos, dry toast and a glass of orange juice for a plate of bacon and eggs—in hopes it will keep us skinny almost effortlessly. But these dietary contortions often have unintended consequences. They inspire us to eat more food, for starters. And the food we eat more of? It contains more chemicals, starches and sugar. These ingredients “are more harmful than the much-feared animal fats,” says Irina Baumbach, secretary of the Association for Nutritional Medicine and Dietetics in Aachen, Germany.
It’s a shame, really. Because as it happens, experts now recognize fat can be good for you. Aside from the beneficial effects some fats can have on cholesterol—unsaturated fats, like olive oil, tend to raise levels of good cholesterol and lower levels of the bad stuff—fats help deliver vitamins, build cells and regulate hormones. Unsaturated fat also has antioxidant properties, which may help fight cancer; so does meat from grass-fed animals. The oft-repeated hypothesis that links a high-fat diet to breast cancer has never been proved. And when it comes to appetite, hunger and obesity, fats—along with protein, green vegetables and whole grains—take more time to digest, making people feel full longer.
Even critics of high-fat diets acknowledge that people on them tend to eat less because they aren’t as hungry. And according to studies published recently in the New England Journal of Medicine (NEJM), many people even have a type of fat—known as brown adipose tissue, or brown fat—that burns calories rather than piling them on.
Finally, fatty food appears to be shedding its stigma. Restaurants are featuring ever-fattier cuts of meat; cookbooks extol the virtues of lard. And the more scientists and nutritionists learn, the more they’re willing to concede that vilifying fat isn’t the solution. Says Jennifer Lovejoy, an obesity researcher at the University of Washington School of Public Health: “When people are eating whole food, real food diets, obesity is not a problem.”
At a time when weight loss has become prime-time entertainment, a civic responsibility and a multibillion-dollar global industry, it’s easy to forget that for centuries, doctors worried about malnutrition, starvation and underweight children, points out Gary Taubes. A science journalist, Taubes has been beating the drum in favor of fat for almost a decade. His book, Good Calories, Bad Calories: Fats, Carbs, and the Controversial Science of Diet and Health (Vintage), spends 500 pages dismantling the prevailing ideas about fat, weight gain and health. It hasn’t made him popular.
There was a time, though, when a low-fat diet was just as controversial. Fat—on the plate or the hips—didn’t trigger health concerns until the late 20th century. As recently as the 1970s, dietary guidelines included plenty of fats and protein, because they helped people feel sated, preventing overeating. And obesity wasn’t considered a serious problem in Europe or the U.S.; high-carbohydrate meals were associated with weight gain, and academic articles linked obesity in Africa and the Caribbean with starchy diets.
But heart disease was a growing public health concern. By the mid-1900s, it was a leading cause of death in the U.S., with the rest of the West catching up quickly. Led by University of Minnesota physiologist Ancel Keys, scientists linked heart disease to cholesterol, and made the leap to fatty foods. While critics of Keys’ research abounded, the U.S. Congress wasn’t among them. In the late 1970s, a Senate committee issued broad dietary guidelines encouraging Americans to eat less fat. Today, we take it for granted that one too many bacon double-cheeseburgers will give us a heart attack for sure.
It’s hardly that simple. While the West started avoiding fats at all costs, researchers continued to study what causes heart disease. As they discovered more about the effects of different kinds of fats—saturated, trans, mono- and poly-unsaturated—on different kinds of cholesterol—HDL (“good”) and LDL (“bad”)—the weaker the link between dietary fats and heart disease became. Unsaturated fats, like those in nuts, fish, olive oil and avocado, are fluid at room temperature; they reduce LDL, which causes buildup in the arteries. Saturated fats, found in meat and dairy, chocolate and palm oil are solid at room temperature and their effects on cholesterol is more complicated. Coconut oil, for example, has been shown to raise both good and bad cholesterol levels, whereas some of the fats in dark chocolate and beef have a neutral effect.
In other words, as Taubes puts it, when it comes to cholesterol, food high in saturated fats may be, at worst, a wash. “If you work out the numbers, you come to the surreal conclusion that you can eat lard straight from the can and conceivably reduce your risk of heart disease,” he wrote in 2002. These days, he says he sees evidence of the conventional wisdom everywhere, from low-fat products on the shelves to the customers at his local bagel shop ordering soy cream cheese and skim lattes. “I always want to ask them why,” he says. “There’s this overarching idea that fat is bad for you—that something has to be the problem with our diets, because we die of heart disease and we get fat.”
Increasingly, researchers and nutrition experts are starting to come around. “I have been in this business for 35 years and I have never been one of those who maintain that fat is bad,” says Daan Kromhout, a professor of public health at Wageningen University in the Netherlands. “We don’t even know whether the two things—fat and [being] overweight—have anything to do with each other. The fat issue is much more complicated than it was once thought to be.” Moreover, Kromhout says, stating only the amount of fat in a food product is misleading, since “you have to specify what type of fat is included—saturated, unsaturated, trans-fat—because if you don’t, people will just cut down on all fats, the good ones included.”
Dutch pediatricians were so alarmed by the low-fat trend that they urged parents to ensure that their children receive the essential nutrients only fat can bring. “Children under the age of 6 need fat,” said Elise Buiting, president of the Dutch Youth Service Medical Association, in an interview with a Dutch newspaper this year. “We recommend full-fat margarine with unsaturated fatty acids, for example. Children who are given the same ‘light’ products as their parents do not get enough.”
As for the connection between fatty foods and weight, it’s controversial as well. Obesity was never the target of Congress’ efforts, although the low-fat recommendations were instituted to help people manage their weight. They haven’t. Since the guidelines were adopted, Americans have indisputably gotten fatter. “In the early 1990s, we ate low-fat everything and we didn’t get thinner,” says Alice Lichtenstein, a professor of nutrition science and policy at Tufts University in Massachusetts. “There’s your proof.”
In the 1960s and ’70s, roughly 14 percent of Americans was obese. Today, more than 30 percent is, with another 30 percent classified as “overweight.” Same goes in Europe, where consumption of fat has dropped and obesity rates have risen. In the U.K., obesity rates have tripled since 1980. In the Netherlands, the percentage of moderately overweight adults increased from 28 in 1981 to almost 36 in 2008, according to the Dutch Central Bureau of Statistics. The percentage of obese people more than doubled, from 5.1 percent to 11.2 percent, in the same period. According to the Society for the Study of Obesity, roughly half the population of the European Union is overweight or obese.
In three decades, while scientists have learned more about what eating fat will and won’t do, consumers have wholeheartedly embraced the “low-fat” doctrine. In the 1990s, more than 1,000 reduced- or low-fat foods were introduced each year, according to the AHA. By the end of the decade, more than 90 percent of the population reported consuming low-fat products. According to one survey, two out of three adults believed “a need exists for food ingredients that can replace the fat in food products,” and one out of every two saw the appeal in food advertised as “reduced in both fat and calories.” In other words, given the chance to replace fat with something else, we opened wide.
So given the blanket condemnation of fat, what did we eat instead? If we cut fat out of our diets, we have to get calories from somewhere. When food companies offer reduced-fat versions of cookies, salad dressings and sauces, sugar and carbohydrates generally make up the difference. When we consciously reduce the fat in our diets, we don’t typically eat fewer calories; we eat more rice and pasta, according to a survey by the U.S. Department of Agriculture. And low-fat products have their own problems. “If you reduce the fat, you have to replace it with something,” says Samuel Klein, a professor of medicine and nutrition in the medical school at Washington University in St. Louis, Missouri. “So it’s sugar.” It’s true: Either for taste, or to replace fat’s richness and moistness, the food industry began using sugar.
But as researchers studied fat and weight, they learned more about the effects of sugar, which as it turns out may inspire more weight gain than fat does. When we eat sugar—or refined carbohydrates, which break down into sugar—the body produces insulin to transport the sugar to the muscles and organs that burn it as fuel. Insulin, though, also regulates fat metabolism, and when insulin levels are high, the body stores fat rather than burning it. The issues and consequences of producing too much insulin are still open to debate, but many researchers believe that replacing fats with sugars and carbohydrates has the potential to wreak havoc on your metabolism. And ironically, even sugar substitutes, like aspartame, the sweetener in NutraSweet and Equal, have been linked to weight gain. Scientists aren’t sure why, but they seem to encourage people to eat more, or disrupt energy expenditures.
Sugar substitutes work well for baked goods, salad dressings and processed meats. But they can’t be fried, making them useless in potato chips, which account for 35 percent of the $46 billion global market for savory snacks, according to the research firm Datamonitor. So food scientists developed an indigestible fat, sucrose polyester—more commonly known by its brand name, Olestra. Researchers found Olestra inhibits the absorption of fat-soluble vitamins and other important nutrients.
Overall, as Americans replaced regular foods with low-fat products, nutrition sometimes suffered. One study found that women who used fat-modified products weren’t getting enough vitamin E or zinc, prompting the authors to recommend “additional dietary guidance.”
Study after study found that people who said they ate low-fat diets didn’t eat any less than people who kept eating fat. The government’s message had perhaps worked too well. People thought fat, not quantity or quality of food, was the villain. The Food Marketing Institute in Virginia reported that buying food products labeled “low-fat” was the most common way people improved their diets. According to Pierre Chandon and Brian Wansink, marketing professors at INSEAD in France and New York’s Cornell University respectively, subsequent studies showed that “low-fat labels lead all consumers—particularly those who are overweight—to overeat snack foods.” After all, a reduced-fat version of a cookie often has just as many calories as its “original” counterpart (not to mention more sugar). Chandon and Wansink extended their theory to fast-food restaurants that claim to be healthy. When foods are perceived to be good for you people eat too much of them.
Fortunately, the tyranny of the low-fat diet seems to be waning. Three years ago, Toronto-based chef and food writer Jennifer McLagan struggled to drum up interest for her idea for a cookbook about animal fat. Her 2005 effort, Bones: Recipes, History, and Lore, had won a James Beard Award, annually conferred on the best chefs, cookbook authors and restaurateurs in North America. Even with that pedigree, fat, apparently, was pushing it. Polite publishers told her the concept was too contrarian. Others flat-out called it “disgusting.”
She eventually found a taker, and her book, Fat: An Appreciation of a Misunderstood Ingredient, with Recipes, with Recipes, is unapologetic. It’s adamant in its defense of fat’s benefits; the cooking instructions range from how to render your own pork fat to recipes for Brown Butter Ice Cream and Bacon Baklava. And McLagan is winning followers. Pork belly and marrow are common on menus; barbeque has gathered legions of fans outside its native South; it seems in every major city you can find at least one restaurant willing to roast a whole pig for a hungry party. And guess what? In May, Fat too won a James Beard Award.
As the obesity epidemic was later to arrive in Europe, the pro-fat backlash isn’t yet in full swing there, but signs are emerging. A recent study in the NEJM fingering total calories, not fats or carbs, as responsible for weight loss, made headlines on both sides of the Atlantic. And anecdotes abound. British celebrity chef Anthony Worrall Thompson has been blatant about using lard in his restaurants. In Norway, sausage consumption is up.
Even mainstream nutritional experts have recanted. The blanket message that “fat is bad for you” has few remaining adherents. The AHA, the National Heart, Lung and Blood Institute and the American Council on Science and Health have all modified the message, from their original admission that unsaturated fats are good for you to the grudging acknowledgement that even trans fats may not be as bad as they’ve been portrayed to be. “We should apologize for making people think about ‘percentage of calories,’” says the AHA’s Eckel, adding that the focus should be on total calories. “You want to eat steak? That’s fine. Just make it six ounces rather than 16.”
To undo decades of fat-phobia, it’s going to take a more rousing endorsement. And for that, it’s necessary to leave the realm of science and enter the kitchen, where it’s easier to consider the possibilities. Take guacamole, or the pat of butter that finishes a risotto or a chocolate pudding. McLagan includes fat in everything from salad to dessert, with recipes for grilled steak and red wine sauce topped with bone marrow. For a sweet, try salty bacon brittle with pork cracklings. These are beyond rich—the animal fats give the dishes depth and an almost medieval earthiness—and they’re delicious, enough to make even confirmed skeptics salivate.
“Go ahead,” McLagan says. “It won’t kill you.”
Janet Paskin, who wrote about social stock markets in the May issue, gained three pounds reporting this story. This story has reporting by Ursula Sautter.