For decades, health officials and the news media demonized fat.
Saturated fat was blamed – inaccurately, we now know – for heart disease.
Unfounded fear of fats led to a disastrous rush to replace them with carbohydrates.
That shift was a deadly mistake, because refined carbs promote heart disease, obesity, diabetes, and dementia.
The rapid rise of the Atkins and Paleo diets helped redeem the image of dietary fat … especially saturated fats.
It's long past time to rebalance the conversation on fats … and balance our intakes of the various kinds.
The dangers of America's omega-6 excess
Plant foods contain substantial amounts of polyunsaturated fat.
Polyunsaturated fats belong to either of two distinct families: omega-3 and omega-6.
The cheapest, most commonly consumed, "bad" vegetable oils – soy, corn, safflower, sunflower, and cottonseed – are very high in omega-6 fats.
An alarming evidence review from the University of Toronto reinforced the dangers of excess omega-6 fat intake.
- Replacing saturated fats with omega-6-laden vegetable oils raises the risk of death from cardiovascular disease, even though these oils lower blood cholesterol levels.
- Health authorities should reconsider the claim that omega-6 fats reduce the risk of heart disease.
Vegetable oils: The best choices
Fortunately, there are several good alternatives to the "bad" omega-6-laden oils:
- Macadamia nut oil is very low in omega-6s, and very high in heart-neutral monounsaturated fat.
- Extra virgin olive oil is low in omega-6s, and rich in both heart-neutral monounsaturated fat and potent antioxidants that enhance artery health.
- Coconut oil is very low in omega-6s, and high in particularly healthful saturated fats (see "Coconut oil: A rising nutritional star", below).
- Sunflower oils labeled "high-oleic" are very low in omega-6s, and very high in heart-neutral monounsaturated fat (oleic acid).
- Canola oil contains substantially less omega-6 fat than the "bad" oils, small but significant amounts of omega-3s, and lots of heart-neutral monounsaturated fat. To avoid GMO canola oil, look for organic brands.
Coincidentally, the American Heart Association just granted permission to use its HeartCheck Food mark on olive oil labels.
Olive oil of any grade is clearly preferable to oils high in omega-6 fats.
But ideally, the AHA should require that the HeartCheck Food label on olive oils mention the superiority of extra-virgin grade olive oils for cardiovascular health.
Saturated fats: No longer considered villains
The decades-long demonization of saturated fats has been a deadly distraction … one that hid the dangers of excessive omega-6 intake.
Last year, the results of an evidence review by scientists at Toronto's McMaster University further demolished the myth that saturated fat is a heart risk (de Souza RJ et al. 2015).
Their analysis of 50 prior studies detected no links between saturated fats and increased risk of death, heart disease, stroke, or Type 2 diabetes.
We recommend these related articles from our archive:
Saturated fats come in several different forms, each of which has different effects on cholesterol profiles.
For example, much of the saturated fat in red meat and cocoa butter (the primary fat in chocolate) is a type known as stearic acid.
Compared with other saturated fats, stearic acid improves cholesterol profiles slightly … and worsens them slightly compared with oils rich in polyunsaturated fats.
Another family of saturated fats – called medium-chain triglycerides or MCTs – also appears pretty safe for cardiovascular health.
Fast-growing evidence that MCTs are relatively healthful helps explain the fast-rising popularity of coconut oil.
Trans unsaturated fats: Villains, but disappearing fast
In their 2015 evidence review, the McMaster University team confirmed the link between trans fats and increased heart risks.
Trans fats are altered forms of unsaturated fats – mostly omega-6 fats – produced when vegetable oils are partially hydrogenated to solidify them and make them resistant to rancidity (oxidation), for use in margarine, and to lengthen the shelf life of packaged foods.
Under pressure from health authorities and consumers, most food manufacturers have removed trans fats from their products, or greatly reduced the amounts.
Coconut oil: A rising nutritional star
Coconut oil is a favorite among fans of the Paleo and "Bulletproof” diets.
And it's one of the few plant oils – along with cocoa butter – rich in saturated fats.
is about 92 percent saturated fats, but most of them are medium chain triglycerides (MCTs).
Thanks in part to its abundance of MCTs, coconut oil exerts a generally neutral effect on people's cholesterol profiles:
- Compared with other saturated fat sources, coconut oil lowers LDL ("bad”) cholesterol levels slightly, and raises HDL ("good") cholesterol levels slightly.
- Compared with monounsaturated fats (abundant in olive oil) and omega-6 fats (abundant in cheap vegetable oils), it raises LDL levels slightly and lowers HDL levels slightly.
Although coconut oil appears to raise blood triglyceride levels slightly, it does not (unlike cheap oils high in omega-6 fats) promote inflammation ... which is a major risk factor for cardiovascular disease.
Coconut oil also appears to help with weight management, probably because the body tends to burn MCTs as fuel, rather than store them as fat.
In fact, MCTs promote ketosis ... the beneficial metabolic state induced by very-low-carb diet programs such as the Atkins and Paleo plans.
This helps explains why coconut oil appears to improve blood sugar and insulin control, and possibly help prevent or ameliorate diabetes.
For the same reason (ketosis), coconut oil may also aid people with mental fog or Alzheimer's, who typically have difficulty using blood sugar to fuel brain functions.
Preliminary evidence indicates that saturated MCT fats – like those in coconut oil
– get around this barrier, and thereby modestly improve memory and thinking.
What does this all mean?
We offer three recommendations:
- Don't replace calories from fat with calories from refined carbs.
- Balance your intake of polyunsaturated, monounsaturated and saturated fats.
- Avoid the vegetable oils highest in omega-6 fats: corn, soy, cottonseed, and regular, (low-oleic) versions of sunflower and safflower oil.
It's important to remember that fat contains twice as many calories as carbohydrates or protein, so it doesn't make sense to overdo any kind of fat.
Finally, it's smart to get most of your fats from nutrient-dense whole foods like fish, grass-fed meats, nuts, legumes (beans and lentils), and dark, leafy greens.
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