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.”
Next: The History of the Low-Fat Weight-Loss connection