by Sharon Liao
For years, fat was a dietary Public Enemy Number One. We were told that it was the culprit responsible for weight gain, health issues and more. As a result, we stocked our kitchens with skim milk, low-fat salad dressings and fat-free cooking spray.
But lately it seems that fat has made a comeback: A coworker recently switched from skim to whole milk. A friend from mat class swears by coconut oil. Another pal started a diet that recommends butter. Instagram is full of pictures of fried eggs, endless avocados and smoothie bowls topped with giant hunks of nut butter. What’s a health-conscious person to believe? “When it comes to fat, there are a lot of mixed messages out there,” says Lisa Cimperman, MS, RDN, a clinical dietitian at University Hospitals Cleveland Medical Center.
To help you cut the confusion, we posed some big fat questions to the experts. Their answers can help you get the skinny on how much fat you should eat, what types are healthiest—and why you can’t add bacon to every meal (sorry!).
Q. Wait, didn’t experts tell us we should cut back on fat?
A. Chances are you’re thinking of the fat-free craze of the 1980s and ’90s. That all started when the government advised scaling back on fat in its 1977 Dietary Goals for the United States, with recommendations that were based on a string of studies linking fat and cholesterol with heart disease, heart attack and stroke.
Remember the U.S. Department of Agriculture’s food pyramid plastered in doctor’s offices, in the school cafeteria and on the side of cereal boxes? Its guidelines reflected the thinking at the time: At the bottom was bread, rice, cereal and pasta—foods Americans were told to center their diets around. The tip of the pyramid included fat and oils, which we were instructed to use sparingly. This advice led people to trade their eggs and bacon for cereal with skim milk for breakfast, swap pretzels for potato chips at snack time and order pasta instead of steak for dinner.
The food industry also jumped on board by removing fat from its products. Fat-free items, such as salad dressing, yogurt and cookies like SnackWell’s—the poster child of the craze—flooded grocery store shelves. “But when you take fat out of a food, you also cut out much of its deliciousness,” explains Lily Nichols, RDN, a registered dietitian, Pilates instructor and owner of the Pilates Nutritionist. To make up for the flavor shortage, manufacturers added other ingredients, like sugar, flour and salt, to their foods.
The result: Americans ate less fat and more carbohydrates, often in the form of sugar and white flour. This may explain the country’s expanding waistline. “Today’s obesity epidemic was caused, in part, by the low-fat era,” says Cimperman. According to the Centers for Disease Control and Prevention, the number of obese Americans soared during that time, from roughly 15 percent in 1976 to 35 percent in 2012. Rates of type 2 diabetes also skyrocketed.
Q. Why did the opinion on fat change?
A. When scientists studied these low-fat diets, they uncovered surprising results. For one, they didn’t deliver the expected health benefits. “Experts found that decreasing fat intake didn’t reduce the risk of chronic diseases,” says Cimperman. Case in point: A series of studies published in 2006 in the Journal of the American Medical Association found that women put on a low-fat eating plan didn’t have more protection against heart disease, breast cancer or colorectal cancer. What’s more, they didn’t lose any more weight than those not on the diet.
Q. Does fat have any health benefits?
A. Put simply, you need fat to survive. That’s because the nutrient has many crucial jobs. It gives you energy, helps regulate your body temperature, and protects your bones and organs. It also plays a role in fertility. “Plus, fat keeps your hair and skin healthy,” says Mascha Davis, RD, a registered dietitian, spokesperson for the Academy of Nutrition and Dietetics and owner of Nomadista Nutrition.
As if that wasn’t enough, fat allows your body to absorb important nutrients, such as vitamins A, D, E and K. These nutrients do everything from fortify your bones to fend off cancer. They also boost levels of heart-healthy antioxidants: According to a 2004 study published in the American Journal of Clinical Nutrition, people who ate a salad topped with full-fat dressing had higher levels of lycopene and carotenoids than those who drizzled on a reduced-fat version.
Q. So, does this mean I should slather coconut oil on everything?
A. Unfortunately, these benefits don’t grant you an all-access pass to fat. It’s important to know that there are different types, says Davis. There are two main categories that have opposite health effects.
Saturated and trans fats are the “bad” kinds, found mainly in animal products and processed foods, such as steak, bacon and store-bought frosting. Saturated fat is also found in tropical oils, such as the new “it girl” fat, coconut oil, as well as in palm oils. Palm oils are found in everything from so-called healthy “butter” substitutes to packaged cookies. Saturated fats up the amount of artery-clogging LDL cholesterol in your blood, which can set the stage for heart attacks and stroke. According to a 2016 Harvard study, for every 5 percent increase in saturated fat you add to your diet, your risk of heart disease jumps by 17 percent.
Trans fats are even worse: They lower the good-for-you HDL cholesterol, which helps keep your arteries clear. They’re so unhealthy that the FDA has banned added trans fats, a regulation that goes into effect nationwide in 2018. Until then, steer clear of products containing partially hydrogenated oils, a code name for trans fats.
On the other hand, unsaturated, or “good,” fats may boost your heart health. There are two types: Monounsaturated fat is found in olive oil, avocados and nuts. Polyunsaturated fat is the kind in soybean oil, fish, walnuts and flaxseed. Experts recommend making these fats your main source. In fact, a 2017 study published in Circulation found that replacing saturated with unsaturated fat can reduce the risk of heart disease by 30 percent. That’s the same effect as taking a cholesterol-lowering medication.