- Dietary fat, especially saturated fat, has been considered unhealthy for the past several decades
- New research shows the cardiovascular risks of eating saturated fat may be overblown
- Certain types of saturated fats might actually be good for you
- Balance the amount—and the type—of fats you eat for a healthy diet
Is there a phrase that gets a brisker workout these days than “healthy fats“? Avo toast rules brunch menus and Instagram feeds, EVOO flows like wine over roasted veggies, and nut butter whir to the beat of smoothie blenders.
But naturally, that brings us to the idea of “unhealthy” fats. What to make of those saturated varieties—the meats, the dairies? The fats that we’ve been told for decades will raise our cholesterol, clog our arteries, and, ultimately, cause heart disease?
Studies have been quietly accumulating over the past few years that suggest the truth about saturated fat is more complicated—and less damning—than previously thought. In fact, the saturated stuff may be necessary, even. . .healthy. Well, be still our beating hearts.
The Debate Over Saturated Fat
This new doctrine hit the big time late last summer when the journal Lancet published a decade-long study looking at the eating patterns of 135,000 people from 18 countries. The startling results got the scientific community squabbling and inspired a flurry of incendiary headlines (“Low-Fat Diet Could Kill You,” for one).
The study found not only that those who consumed the least fat and most carbohydrates had a 28 percent higher risk of dying over those 10 years, but also that those eating the most fat had a 23 percent lower risk for death. More pointedly, those results held steady across all kinds of fats—including saturated fats, which showed an additional benefit of being associated with a lower stroke risk. And low levels of saturated fat actually increased mortality risk.
Shocking news and not everyone is on the same page. The American Heart Association still recommends that saturated fat be less than 6 percent of an adult’s daily calorie consumption, a tiny amount considering that the average saturated-fat consumption in the U.S. is around 14 percent. But altering dietary recommendations can be like turning an ocean liner that’s going full steam ahead: It’s a slow and unwieldy process.
“There has been a lot of discussion of the evils of saturated fats for many years,” says Rita Redberg, M.D., a cardiologist at the University of California San Francisco School of Medicine and the editor of JAMA Internal Medicine. “Re-education based on new knowledge and understanding takes time.”
Meanwhile, our efforts to avoid sat fats have led us to try to replace them—with mixed results. The first suggestion, carbs, turned out to be catastrophic, with many experts now suggesting it triggered our current obesity crisis. Now the anti-sat-fat camp recommends “replacing saturated fat with unsaturated fat as much as reasonably possible,” says Walter Willet, M.D., a professor of epidemiology and nutrition at Harvard University, who has studied diet’s effect on health for 40 years.
But concerns are arising about unsaturated fats as well, particularly one category of polyunsaturated fats (PUFAs): certain vegetable oils, such as corn and soybean, that are high in omega-6 fatty acids (as opposed to those high in omega-3s, which are clearly health-promoting).
The thicket of conflicting messages is frustrating. But there is a way through the brambles, a path that follows the evidence and weaves in common sense too. Because fat is as essential as it is delicious, we dove deeper into what kind you should be putting on your plate.
Eat a high-fat Mediterranean diet. Reduce stress. Walk at least 22 minutes a day. Take the focus off saturated fat. When Redberg and two other cardiologists published an editorial in the British Journal of Sports Medicine last April proclaiming all of the above, the backlash from old-guard scientists was swift and stinging, labeling the advice “bizarre” and “simplistic.”
Yet a growing tally of studies seems to suggest that it is neither, calling decades of assumptions about saturated fat into question. One was a meta-analysis in 2014 that looked at 76 studies—27 of the randomized, controlled trials, the gold standard for research—and found that “current evidence” doesn’t support limiting saturated fats in favor of PUFAs.
Another analysis the next year showed no link between saturated fat intake and mortality from all causes, including cardiovascular disease, heart disease, and type 2 diabetes. “Saturated fat used to be public-health enemy number one,” says David Ludwig, M.D., Ph.D., a professor of nutrition at the Harvard, T. H. Chan School of Public Health. “But it’s neither that nor exactly a health food. It’s kind of a neutral.” Here’s a primer on the evolving science of saturated fats in your body.
It impacts cholesterol.
But not in the way you think. What really matters: the ratio of LDL to HDL. The higher your HDL (the protective cholesterol), the better. “Saturated fat raises LDL, but it also raises HDL and lowers triglycerides,” says Ludwig.
Not all LDL is alike.
Emerging research suggests there are two kinds of LDL particles: big, fluffy particles that protect against heart disease, and small, dense particles that may create inflammation and blockage.
The source of sat fat is key.
We now know that not all saturated fats behave the same in the body. Full-fat dairy and dark chocolate are full of sat fats but don’t raise the risk for cardiovascular disease.
It helps control weight.
In fact, Ludwig claims we should eat more fat in general and far fewer processed carbs for our health and waistlines. “When you consider white bread and butter, the bread is the less healthful component,” he says. After conducting research for 20 years, he created a weight-loss program outlined in his 2016 book, Always Hungry? In a pilot test, the average weight loss over 16 weeks was 20 pounds, with some ranging to 30. “Since the program is not calorie-restricted, we also think the results will be more sustainable,” he adds.
The plan calls for a diet that’s 50 percent fat in the first two weeks, with 25 percent each for carbs and protein. Then the level falls to about 40 percent fat, depending on the person. Perhaps not coincidentally, that is where the average American fat intake stood before the vilification of fats, and especially saturated fat, that began in the ’70s—and before the obesity epidemic.
Hard to Process
Peer into most American cupboards and you’ll find them: bottles of corn, soybean, and canola oils. These polyunsaturated oils are hugely popular and marketed as healthy, particularly when compared with butter. They also contain large amounts of omega-6 fatty acids. Those are a good thing, right? Not so fast.
Omega-6s are something of an evil twin to omega-3s, the heart-healthy fats in fish and olive oil. We do need a bit of omega-6 in our diets, but we now take in vastly more than we did a century or so ago—thanks to all that processed vegetable oil—and recent research suggests it may promote heart disease rather than protect against it.
One of the most convincing studies was published in 2016 but was based on evidence collected in the ’70s. (Why, you ask? Some experts feel it was “buried” because it didn’t support the pro-vegetable oil theory of the day.)
The large clinical trial hypothesized that reducing saturated fat and replacing it with omega-6-loaded corn oil would prevent heart disease and lower mortality rates. Instead, it did nearly the opposite, and in surprising ways. Cholesterol levels did go down in the corn-oil group, but death rates stayed the same as in the sat-fat group. And the greater the drop in cholesterol, the higher the chance of death.
The evidence is mounting, says James DiNicolantonio, PharmD., a cardiovascular research scientist at Saint Luke’s Mid America Heart Institute in Kansas City, Missouri, and author of The Salt Fix. Specifically, he cites a meta-analysis that suggests the ratio of omega-6 to omega-3—just like that ratio of LDL to HDL regarding saturated fat—is especially important.
It all comes down to inflammation. Omega-6 causes it, contributing to cardiovascular disease, cancer, osteoporosis, and autoimmune diseases. Omega-3 protects you from it. So rejigger your diet by increasing your intake of fatty fishes like salmon and tuna, flaxseed, grass-fed (not grain-fed) beef, walnuts, and lentils. And minimize your consumption of vegetable oils, bottled salad dressings (also sugar-laden), and snacks like crackers. It’s an easy ratio we can all get behind.
Striking A Healthy Balance
Experts have long suggested that the “French paradox”—the fact that people in that country eat more saturated fats than we do, yet live longer and have much less heart disease and obesity—is due to their way of life: They cook more and are more active (not necessarily gym workouts, just walking). And though their food is often high in fat (think duck a l’orange), it’s served in smaller portions and eaten in a leisurely way. They rarely count calories or fat grams. That same moderation should inform your own diet. Here’s how to start:
Choose whole, “real” foods over those that come packaged.
Processed foods, even those with “no trans fats!” labels, tend to be high in polyunsaturated fats.
Limit eating out.
And not just because of huge portions: The restaurant industry relies heavily on polyunsaturated oils and also typically uses high heats. That causes the oils to oxidize and even creates trans-fatty acids; both raise heart disease risk.
Don’t obsess over counting fat grams.
Eat a variety of foods (some meats, balanced out with lots of fish and non-animal sources of protein like legumes), and plenty of vegetables. If you’re eating enough fat, you’ll be naturally satiated.