Americans have a case of nutritional whiplash when it comes to dietary fat. For decades we’ve been told that reducing our fat intake can prevent weight gain and ward off disease, so we’ve dutifully filled our grocery carts with low-fat, reduced-fat, and fat-free fare. But in recent years the case against dietary fat has begun falling apart.
A growing number of medical experts and organizations are challenging the demonization of dietary fat as the key cause of cardiovascular maladies. And now we know, after the release of a study in JAMA Internal Medicine in September 2016, that a sugar-industry trade group paid Harvard scientists to release nutritional studies, starting in 1965 and continuing through the 1970s, that downplayed sugar’s role and instead pointed the finger at saturated fats and cholesterol. In recent years, multiple peer-reviewed studies have suggested that the epidemic of heart disease — as well as other chronic illnesses such as type 2 diabetes and cancer — are more likely the result of diets high in refined carbohydrates and sugar. (For more on the latest thinking on cholesterol and the heart, see ELmag.com/hearthealth.)
“The low-fat era is finally starting to come to an end,” says Mark Hyman, MD, director of the Cleveland Clinic’s Center for Functional Medicine and author of Eat Fat, Get Thin: Why the Fat We Eat Is the Key to Sustained Weight Loss and Vibrant Health. Indeed, after 35 years of advising a low-fat, low-cholesterol diet, the U.S. Dietary Guidelines largely exonerated dietary fat and cholesterol in 2015.
That’s good news for those of us who find whole-egg omelets and full-fat yogurts to be more satisfying and filling. And besides, those low- and no-fat foods haven’t done our bodies any favors.
We need fat for a wide range of health-promoting metabolic functions, including building cell membranes, producing hormones, absorbing vitamins, protecting our nerves, moderating our glycemic load, and supporting basic brain functions. When we don’t get enough fat in our diets, we feel hungry a lot of the time and end up craving unhealthy foods.
“Low-fat diets have had unintended consequences, turning people away from healthy high-fat foods and toward foods rich in added sugars, starches, and refined grains,” notes cardiologist and Harvard Medical School professor Dariush Mozaffarian, MD, in a JAMA commentary on the new guidelines. “This has helped fuel the twin epidemics of obesity and diabetes in America.”
Rates of these two diseases have been skyrocketing for years. So, beyond the falsified nutritional studies of the past, why has it taken so long for experts to realize that our low-fat obsession is making us sick?
According to Hyman, many other studies were difficult to interpret because they were poorly designed. “These are studies in which people who are eating fat are eating bad fats, inflammatory fats, and junk foods,” he says. “Of course you would think that fat is bad for you if you’re looking at a study like that.”
Additionally, it takes a long time for emerging research to trickle down to the institutions that translate it and set nutritional policy, says Mark Pettus, MD, associate dean of medical education at the University of Massachusetts Medical School and director of medical education, wellness, and population health at Berkshire Health Systems in western Massachusetts.
“We’re in the midst of a knowledge revolution right now,” Pettus explains. “In 2016, medical knowledge is doubling every month or two.” The organizations that we look to for nutritional information — whether it’s the USDA, American Heart Association, or others — are slow to respond and create new guidelines, he says.
Although good fats are essential to our overall health, many people still feel anxious about embracing them. It was one thing when we had to avoid all fats; now we have to figure out which fats are healthy — and that can be overwhelming.
In particular, people tend to be leery of anything containing saturated fat, without considering its source or context. The saturated fat in grassfed beef, for example, or in coconut oil (which delivers health-supporting medium-chain triglycerides, or MCTs) is very different from saturated fat found in processed meats and packaged foods.
Many progressive health experts believe saturated fats have been unfairly disparaged, mainly because they are often lumped in with processed trans fats, which were deemed “not generally recognized as safe” for human consumption by the FDA in 2015.
“I think most saturated fats are probably much healthier than we thought,” says Pettus, “especially when they are being ingested from quality sources — and especially if people are not eating a lot of refined, poor-quality carbs and sugar.”
Hyman agrees. “Not all saturated fats are bad, but they’ve somehow been grouped together and labeled as harmful. Healthy saturated fats can actually help you burn fat, make your brain work better and faster, make your skin glow, and help optimize your cholesterol profiles.”
He cautions, however, that “quality becomes paramount here. The saturated fat in a fast-food bacon cheeseburger will have an entirely different effect than saturated fat in coconut oil.”
Hyman explains that saturated fat should be consumed as part of a diet low in refined carbohydrates and sugar. He cites a recent study of prediabetics that compared the levels of saturated fats in their blood as they moved through various diets that ranged from lower carb and higher saturated fat to higher carb and lower saturated fat. Only when participants ate a diet high in carbs did researchers see a spike in saturated fats in their blood.
Other research supports the idea that saturated fats have gotten a bad rap. A meta-analysis published in 2010 in the American Journal of Clinical Nutrition examined 21 studies and observed that intake of saturated fat was not found to increase the risk of coronary heart disease, stroke, or cardiovascular disease. Another study discovered that when saturated fat is replaced with high carbohydrate intake — particularly refined carbohydrates — conditions associated with insulin resistance and obesity increase.
The takeaway? Look at your saturated-fat intake within the context of your overall diet.
“Anyone who goes from a standard American diet to a diet that reduces sugar, eliminates poor-quality carbohydrates and poorly sourced animal foods, and who moves toward less-processed food — including less-processed fats — will only see an improvement in their health,” says Pettus.
Read on for more expert advice on how to incorporate healthy fats (saturated and unsaturated) into your nutrition repertoire — plus a handy guide to the best fats and oils to keep in your kitchen.
FATS IN THE KITCHEN
To enjoy the healthiest results, choose organic, unrefined fats. Think about the flavor you want, and choose the appropriate fat for the cooking heat. Experiment with our experts’ favorites, listed here by cooking-heat recommendations — or keep things simple and stick with extra-virgin olive oil, butter or ghee, and coconut oil.
|GOOD TO KNOW|
|Ghee||High||Animal dairy||Saturated||Keep in a cool,|
|Ghee is butter that has been clarified|
to remove the milk solids; it has a much higher smoke point than butter
|Coconut Oil||Medium-high||Fruit||Saturated||Keep in a cool, dark place||This is a great source of medium-chain triglycerides (MCTs), which have numerous health benefits.|
|Butter||Medium||Animal dairy||Saturated||Keep in a cool, dark place, or refrigerate||Butter from grassfed cows delivers health-promoting fatty acids and other nutrients.|
|Medium||Fruit||Monounsaturated||Refrigerate||Choose unfiltered oil: cloudiness indicates the presence of phytochemicals and other healthy compounds.|
|Avocado Oil||Medium||Fruit||Monounsaturated||Refrigerate||This mild-flavored oil is high in antioxidant carotenoids including beta-carotene.|
Rendered Bacon Fat,
|Medium||Animal fat||Monounsaturated||Refrigerate||For the healthiest nutrient profile, choose organic, unprocessed lard from animals that had access to sunlight and forage.|
|Sesame- Seed Oil||Low||Seed||Polyunsaturated||Refrigerate||While most polyunsaturated fats should not be heated, sesame-seed oil works well in low-heat cooking.|
|Walnut Oil||None||Nut||Polyunsaturated||Refrigerate||Use in raw preparations, such as salad dressings, drizzles, and dips.|
|Flaxseed Oil||None||Seed||Polyunsaturated||Refrigerate||This is one of the richest sources of alpha-linolenic acid (ALA), a plant-based omega-3 fatty acid.|
|Hemp- Seed Oil||None||Seed||Polyunsaturated||Refrigerate||Nutty and herbal in flavor, this is interchangeable with flaxseed oil.|