Many people think vegetable oils are healthy. The word vegetable might have something to do with it. Or maybe it’s the American Heart Association — a group that’s endorsed soybean oil, corn oil, and the rest of the vegetable oils as “heart healthy” for nearly half a century[*].
Whatever the reason, what’s certain is that vegetable oils have made their way into more and more foods (especially processed foods) over the last 50 years, while fats like butter and coconut oil have been phased out.
Vegetable oils have no place on a healthy ketogenic diet. The trouble is that vegetable oils are rich in linoleic acid and other inflammatory and easily oxidized omega-6 fatty acids.
Vegetable oils are bad for your metabolism, inflammation levels, oxidative stress, weight regulation, and cancer risk.
This article will cover the science behind vegetable oils, the top seven vegetable oils to avoid, and what to use instead of vegetable oils.
For the last half-century, the American Heart Association has maintained that saturated fat is a driving cause of heart disease and that for the sake of your heart, you should replace saturated fats like butter and coconut oil with “heart healthy” vegetable oils rich in omega-6 fatty acids.
However, more and more research is coming out that suggests the exact opposite. In the last decade, several large, independent reviews of the research have found thatdietary saturated fat is not associated with heart disease.
The data actually suggests the opposite. Saturated fat intake is inversely correlated with stroke incidence, and may protect against alcohol-related liver disease.
And foods high in saturated fat — eggs, palm oil, and coconut oil — are rich in beneficial nutrients like choline, carotenoids, and medium chain triglycerides (MCTs).
When you store (or eat) fat, you store it in triglyceride form. When it’s time to use that fat for energy — on a ketogenic diet, for instance — the triglyceride is broken down into fatty acids.
Fatty acids are the building blocks of fat. There are a few different types, each with unique effects on your health.
Here are the four major types of fatty acids:
Saturated fatty acid (SFA)Monounsaturated fatty acid (MUFA)Polyunsaturated fatty acid (PUFA)Trans Fatty Acid (trans fat)
You already learned about SFA. SFAs are satiating, resists oxidation, and is stable at high heats, which makes it great for cooking. Contrary to popular wisdom, SFA is healthy.
Next come MUFAs. High MUFA intake correlates with lower blood pressure, lower blood glucose, and lower cardiovascular risk[*].
You won’t find many folks bashing monounsaturated fats. They’re the main type of fat in olive oil and avocado oil, and are prevalent in the Mediterranean Diet, which is one of the best-studied diets for longevity.
Then there are PUFAs. PUFAs can be divided into anti-inflammatory omega-3 fatty acids like the ones you find in fish, and pro-inflammatory omega-6 fatty acids like the ones you find in vegetable oil.
Finally, artificial trans fats — or hydrogenatedPUFAs. Artificial trans fats are by far the worst type of fat around. Luckily, researchers have shown how bad they are, and at this point, trans fats are illegal in most parts of the world[*].
Omega-6 PUFAs aren’t as bad as trans fats, but they aren’t great for you either. Let’s talk about why.