“There is a noxious substance in your pantry—and likely your fridge and freezer, too. It has an innocuous and even healthy-sounding name. It is ubiquitous in prepared foods and a staple ingredient in home-cooked meals. Chances are that you and your family are eating it every day. I am referring to vegetable oil—a substance that all of us eat but too few of us know much about.”
Catherine Shanahan, Dark Calories: How Vegetable Oils Destroy Our Health and How We Can Get It Back
Vegetable oils have infiltrated our food supply. More than 80% of packaged foods contain at least one type of vegetable oil, including many products labeled organic, GMO Free, and Whole30 Approved. Because they are cheaper than traditional cooking oils, most restaurants, even those that are high-end, use vegetable oils. So widespread is their use that nearly 30% of the average person’s total calories, and 80% of all fat calories, come from vegetable oils.
“…[vegetable oils] are now the largest single source of dietary fats, accounting for more calories in our diets than sugar or flour.”
Catherine Shanahan, Dark Calories: How Vegetable Oils Destroy Our Health and How We Can Get It Back
Despite the vast quantities people consume, few know that vegetable oils are extremely unhealthy. In this 2 part series, relying on the medical doctor Catherine Shanahan’s book Dark Calories: How Vegetable Oils Destroy Our Health and How We Can Get It Back, we explore why vegetable oils are one of the most dangerous ingredients in our food supply, and why we should avoid them as much as possible.
“…your life-giving biology is under siege—vegetable oils will inevitably make you sick (if they haven’t already)…Unfortunately, doctors, nutritionists, dietitians, and obesity researchers are completely in the dark about the negative health effects of vegetable oil…the link between vegetable oil and poor health is firmly grounded and can be backed up with hard scientific research.”
Catherine Shanahan, Dark Calories: How Vegetable Oils Destroy Our Health and How We Can Get It Back
Vegetable oils do not come from vegetables. They come from seeds, which is why they are also referred to as seed oils. Since both terms are commonly used, we will use them interchangeably in this video. While some cultures have hand-pressed oils from seeds like mustard and sesame for centuries, the seed oils most widely consumed today – such as corn, canola, cottonseed, soybean, sunflower, safflower, grapeseed, and rice bran oil – are a modern invention. Their story begins not on a farm, but in a soap factory.
In the 1890s, Procter & Gamble, which was at the time primarily a manufacturer of soaps and candles, sought a cheaper substitute for the beef tallow they used in their products. They turned to cottonseed oil, which at the time was a waste byproduct of cotton fibre production. With the help of chemists, they developed a process called hydrogenation, which involves adding hydrogen to turn the liquid oil into a solid fat suitable for soap. The result was Ivory soap. But as the hydrogenated cottonseed oil they produced was smooth, spreadable, and inexpensive, Procter & Gamble saw an opportunity to expand it into other markets and in 1911 they started selling cottonseed oil as Crisco, and they marketed it to housewives as “a healthier alternative to cooking with animal fats.”
A few decades later, another agricultural-industrial shift resulted in vegetable oils further infiltrating the food supply. In the 1940s, American farmers started using soy meal to rapidly fatten livestock and keep up with the growing demand for meat; but the animals couldn’t digest the soy unless the oil was first removed. This led to soybeans being processed into two distinct products: oil and meal. While the meal went to animal feed, the oil, initially used in industrial and plastic manufacturing, started to be used as cooking oils and by the 1950s it was added to dressings.
“Thus, vegetable oil has a unique history of being released into the food supply as a byproduct of two separate industries, soapmaking and confined animal feeding operations.”
Catherine Shanahan, Dark Calories: How Vegetable Oils Destroy Our Health and How We Can Get It Back
Unlike traditional plant oils like coconut and olive oil, crops such as corn, canola, and sunflower thrive in diverse climates. This agricultural versatility, along with their ability to be processed into not only vegetable oils but also a range of industrial and food products, made them highly profitable. As a result, starting in the 1950s these oilseed crops became the backbone of a rapidly growing global industry. As Catherine Shanahan explains:
“[The vegetable oil industry] generated more than $115.8 billion in 2020, and that figure is projected to increase to $162 billion by 2027. Candace Rassias is an industry insider who told me that the food service industry as we know it would collapse without vegetable oil.”
Catherine Shanahan, Dark Calories: How Vegetable Oils Destroy Our Health and How We Can Get It Back
To keep up with the massive demand, vegetable oils are produced in large industrial facilities in which they undergo an intensive refining process. First, the seeds are heated and crushed to separate the oil from the solid material, known as the cake. The cake is then washed with hexane – a chemical solvent derived from gasoline – to extract additional oil. The separated oil at this stage is unsafe for consumption, as it contains harmful compounds like aldehydes, peroxides, and inedible waxes and gums. To transform this crude oil into what’s marketed as “edible oil,” it undergoes a series of complex processes, including degumming, dewaxing, deodorizing, and bleaching – the latter of which masks its rancid odor and unpalatable appearance.
“Entire factories may specialize in just one of these major steps. Most flowcharts illustrate between twenty and forty different reaction chambers, each connected by what must amount to miles of tubes. I can’t imagine that any ingredient requires more intensive processing than vegetable oil.”
Catherine Shanahan, Dark Calories: How Vegetable Oils Destroy Our Health and How We Can Get It Back
Despite undergoing heavy industrial processing, the problem with vegetable oils is not so much in how they are made, but what they are made of.
