Is there a phrase that gets a brisker workout these days than “healthy fats”? Avo toast rules brunch menus and Instagram feeds, olive oil flows like wine over roasted veggies and nut butters 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 year, 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% higher risk of dying over those 10 years, but also that those eating the most fat had a 23% 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% of an adult’s daily kilojoule consumption. 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 cardiologist Dr Rita Redberg, 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 Dr Walter Willet, a professor of epidemiology and nutrition, 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 – like olive oil – 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 Dr 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, labelling 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 them randomised, controlled trials, the gold standard for research – and found that “current evidence” doesn’t support limiting saturated fats in favour of polyunsaturated fatty acids (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 Dr David Ludwig, a professor of nutrition. “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 Dr 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, Dr 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 programme outlined in his 2016 book, Always Hungry?
In a pilot test, the average weight loss over 16 weeks was 10kg, with some ranging to 15. “Since the programme is not kilojoule-restricted, we also think the results will be more sustainable,” he adds.
The plan calls for a diet that’s 50% fat in the first two weeks, with 25% each for carbs and protein. Then the level falls to about 40% fat, depending on the person. Perhaps not coincidentally, that is pretty much where the average 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 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.
Not all sat fats behave the same in the body
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 hypothesised 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.
Evidence is mounting, says cardiovascular research scientist James DiNicolantonio, 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 rejig your diet by increasing your intake of fatty fishes like salmon and tuna, flaxseed, grass-fed (not grain-fed) beef, walnuts and lentils. And minimise 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 kilojoules or fat grams. That same moderation should inform your own diet.
Here’s how to start:
1. Choose whole, “real” foods over packaged goods
Processed foods, even those with “no trans fats!” labels, tend to be high in polyunsaturated fats.
2. 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 oxidise and even creates trans-fatty acids; both raise heart disease risk.
3. 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.
This article was originally published on www.womenshealthmag.com
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