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How Can Something Called ‘Vegetable Oil’ Be So Bad for You?

I juice carrots all the time, and I’m fine

Vegetable oil has been mired in controversy in recent years. What was once considered a healthy replacement for animal fats due to its ability to reduce cholesterol, vegetable-based oils are now disparaged by some as the cause of several looming American health problems, and has even had documentaries produced that are dedicated to eliminating it from grocery store shelves. 

So how is it that a product that’s ostensibly produced from vegetables — theoretically the healthiest and most anodyne food products accessible to the masses — can be the focus of such ire?

Yeah, seriously! I thought vegetables were supposed to be healthy!

And I’m sure that’s just what they want you to think.

Scientifically speaking, vegetables are a part of a plant that’s used as food, but not the fruit of the plant. More often than not, true vegetables are the leaf, stalk or root of a plant, like potatoes, carrots, celery, radishes, lettuce and cabbage. If your “vegetable” is actually the fruit of a plant, then it’s a fruit, botanically speaking.

Now let’s move on to evaluating the definition of oil, which refers to any nonpolar chemical substance that’s composed primarily of hydrocarbons that doesn’t mix with water, and does mix with other oils. As a general rule, they’re liquid at room temperature and flammable.

So the name “vegetable oil” is essentially a lie, albeit a lie that stems from a common misunderstanding of food classification. Almost all vegetable oil is processed from parts of fruits. Soybean oil, grape seed oil and cocoa butter are all made from the seeds of fruits. Olive oil, palm oil and rice bran oil are also fats that are derived from the components of what are technically fruits.

The prior definition is with respect to vegetable oils as a group. However, when we’re speaking about the U.S. in particular, almost all of what’s sold specifically as vegetable oil is actually soybean oil, and soybeans are a fruit, because beans are a fruit. I know: Your mind is blown.

Okay, my mind is blown. But I still don’t get how vegetable oil can be unhealthy.

For one thing, you should realize that when the essence of the same oil used to grease your pan is capable of powering a Ford Transit Cargo Van or a GMC Terrain, it has the capability to do horrific damage to your innards if it isn’t handled with care.

Most vegetable oil is either mechanically crushed or pressed out of the fruit or its seed, or it’s commercially processed out of whatever seeds it’s being extracted from by using a solvent. The solvent is then evaporated out of the oil. Next, if the oil is intended to be edible, it’s heated to around 450 degrees and water is introduced to it. The water bubbles through it and carries away all water-soluble chemicals. This process leaves behind what’s regarded as vegetable oil, which isn’t technically considered to be flammable, but which does have a flashpoint like all oils, and which can catch fire if it reaches 600 degrees.

Vegetable oil also oxidizes just like all other oils — including the oil running through your car’s engine. This is critical to understanding the potential unhealthiness of vegetable oil. All oils exist in states of perpetual oxidation, with oxygen exposure and light being the main secondary factors that accelerate the oxidative process. However, the primary accelerant to oil oxidation is the escalation of the heat in the environment the oil has been placed in, and that’s what gets to the heart of the issue, since heat is an essential component of cooking. When edible oils oxidize, they produce free radicals, and those are what cause the real trouble.

What do free radicals do?

Newly formed free radicals cause a buildup of oxidative stress in the body by upsetting the balance between free radical activity and antioxidant activity. When this balance swings too far in the favor of proliferating free radicals, they begin to do damage to the fatty tissues, proteins and DNA that compose the body. As a result, several major diseases can be spawned, including diabetes, heart disease and cancer, along with premature aging. 

It’s not that free radicals are definitionally noxious; they’re actually beneficial under the right circumstances. For example, they possess the ability to fight off pathogens. It just happens to be the case that allowing free radicals to persist untethered will have deleterious effects on your body eventually.

In short, the presumption that vegetable oil is functionally healthy because its name contains the word “vegetable” is putting the focus on the wrong word; the oil is the issue. Whenever any oil or fat — whether it’s animal- or vegetable-based — is heated to a point where it begins smoking, that’s the state at which it’s breaking down and forming free radicals. While most vegetable oils have higher smoke points than animal oils and fats, that doesn’t make them benign, and all of it can do cellular damage to your body, harm to your DNA and kill your body tissue.

I think I’ll stick with my bag of baby carrots.

Solid choice — if for no other reason than the fact that they come in solid form.