Some of the healthiest cultures in the world continue to consume saturated animal fats as their main source of dietary fats. Meanwhile, some of the unhealthiest cultures today consume vegetable oils as their main source of dietary fats.
Only within the past hundred years or so has the consumption of vegetable oils become the norm. After the introduction of the 1977 Dietary Guidelines for Americans, which denounced saturated fats, Americans, in particular, quickly made the shift to making vegetable oils their main source of dietary fat. Coincidentally, obesity rates just so happened to skyrocket the following years, escalating sharply in the 1980s and more than doubling since. Although multiple factors have likely contributed to this, many suspect vegetable oils have been a major culprit.
History of Vegetable Oils in the Human Diet
Today, almost all processed and fast foods in America are made using vegetable oils, but this hasn’t always been the case. Americans have only shifted from using animal fats to vegetable oils in the kitchen mainly in the past 50 years. Prior to the introduction of oils like cottonseed, soybean, and canola in the diet, people across the world have traditionally used animal fats like butter, tallow, duck fat, ghee, and lard for cooking, so what caused this shift?
It began with Crisco, introduced by Procter & Gamble in 1911. Though cottonseed oil was known to be toxic to animals when consumed, it managed to make its way into the human diet under the guise of Crisco, an oil that was formulated by converting fats to toxic trans fats using the hydrogenation process. Once the news came out that trans fats were toxic, Crisco replaced their cottonseed oil with soybean oil, but soybean oil is speculated to be just as problematic, if not more. Crisco was heavily marketed and slowly started making its way into the kitchen.
Though cottonseed oil is toxic to animals, it managed to make its way into the human diet as Crisco.
However, it wasn’t until shortly after WW2 and the introduction of the diet-heart hypothesis, which suggested that eating saturated fats like butter caused heart disease, that the use of vegetable oils really skyrocketed. Between the rapidly increasing mass-production of soybean oil, the excess industrial oil from WW2 being converted into canola oil, and the diet-heart hypothesis being heavily pushed, vegetable oils quickly became a common kitchen item. Especially after the American Heart Association officially declared that people should reduce their saturated fat intake in 1961, vegetable oils eventually became the main cooking oil used in peoples’ kitchens, favored for their “heart-healthy” reputation. The American Heart Association supported the use of vegetable oils, recommending oils like Crisco as a healthy dietary fat replacement for saturated fats (not that a $1.5 million donation from Procter & Gamble had anything to do with it).
It’s well known by nutrition professionals that vegetable oils are still relatively new to the human diet. It’s also common knowledge that consuming saturated fats like butter has been the norm in healthy cultures for thousands of years, yet somehow these fats have taken the fall for obesity and other health issues. Though saturated fats have never seemed to pose an issue in all of history, they’re still villainized to this day, thanks to a man named Ancel Keys and his diet-heart hypothesis.
The Diet-Heart Hypothesis
Despite saturated fats being a normal part of the diet for thousands of years, many insist on them being the main cause of major health issues like heart disease. The idea that saturated fats cause heart disease was introduced as the “diet-heart hypothesis” by a physiologist named Ancel Keys in the 1950s. The diet-heart hypothesis proposes that consuming foods high in cholesterol and saturated fats raises blood cholesterol and causes heart disease.
The diet-heart hypothesis proposes that foods high in cholesterol and saturated fats cause heart disease.
This hypothesis was based on the premise that cholesterol causes heart disease, a concept first introduced by pathologist Nikolai N. Anichkov after feeding rabbits (vegetarians) dietary cholesterol (something their bodies are not used to digesting) and observing a negative effect. Keys pointed to studies like The Framingham Heart Study, and The Anti-Coronary Club Trial to back his hypothesis and carried out his own study known as The Seven Countries Study. However, in the book A Big Fat Surprise, Nina Teicholz makes several points refuting the studies provided by Keys. These points include:
The Seven Countries Study concluded that a diet high in saturated fat causes heart disease due to the fact that 992/10,000 Finnish men, whose diets comprised of 22% saturated fats died from heart disease over a decade vs only 9/10,000 men from Crete and Corfu, whose diets comprised of only 8% saturated fats. However, Keys cherry-picked the seven out of 22 countries that supported his hypothesis when carrying out the study, and he completely ignored the fact that the Cretans ate higher amounts of saturated fats than the Corfiots, but had lower rates of heart disease.
The Framingham Heart Study, an ongoing study, followed the lives of about 5,200 people in the Massachusetts town of Framingham, and concluded after six years that high cholesterol seemed to be a reliable predictor of heart disease. However, after 30 years, the follow-up showed that half of the people in the study who had heart attacks had “normal” cholesterol levels and there was an 11% increase in coronary and total mortality for each 1% mg/dL drop in cholesterol. It’s also been found that 75% of people who have heart attacks have normal cholesterol levels.
The Anti-Coronary Club Trial concluded that a diet low in saturated fats protects against heart disease after finding that men on the “anti-coronary diet,” with 30% of their fat intake coming from vegetable oils, lost weight and had a drop in cholesterol and blood pressure. However, a decade later, 26 diet club members had died compared to 6 of the controls; 8 members died from a heart attack but none of the controls.
Although these studies have been shown to have contradictions, many professionals and experts still continue to insist that saturated fats cause heart disease and rely on these studies as their justification for recommending limited saturated fat intake. However, according to an epidemiological review of the data from several different studies, there is no evidence for any dietary fat intake leading to heart disease, except for trans fats. So if saturated fats aren’t the problem, what is?
The Problem with Vegetable Oils
There are likely multiple different factors that have contributed to the rise of chronic illness and obesity today, but many speculate vegetable oils have a part to play. Unlike olive oil, a monounsaturated fat, or coconut oil, a saturated fat, seed oils are vegetable oils that are composed of polyunsaturated fats. Polyunsaturated fats (PUFAs) are fats that are known to be the least stable, meaning they oxidize easily when exposed to light, heat, or oxygen. Oxidative stress causes free radicals to bind to different proteins, damaging RNA and creating inflammatory compounds. The level of inflammation these free radicals cause can lead to a wide array of health issues including obesity, type 2 diabetes, and cardiovascular disease. This, however, is only one of the reasons vegetable oils are problematic.
Vegetable oils are composed of mainly omega 6 polyunsaturated fats. Although omega 6 fats are not inherently bad, they can be bad when consumed excessively without a proportionate omega 3 intake. Today, Westerners are deficient in omega 3 fats in their diet but consume an excessive amount of omega 6 fats. It’s suggested that humans traditionally ate a balanced 1:1 ratio of omega 6 to omega 3 fats, but today Westerners eat about a 20:1 ratio.
Vegetable oils are the least stable, leading to oxidative stress, inflammation, and disease.
One study states that “excessive amounts of omega-6 polyunsaturated fatty acids (PUFA) and a very high omega-6/omega-3 ratio, as is found in today's Western diets, promote the pathogenesis of many diseases, including cardiovascular disease, cancer, and inflammatory and autoimmune diseases, whereas increased levels of omega-3 PUFA (a low omega-6/omega-3 ratio) exert suppressive effects.”
Another study shows an increased risk of obesity with an increase in omega-6 fatty acids and the omega-6/omega-3 ratio. It’s also been shown that omega 6 fats elevate the level of endocannabinoids in the system, causing weight gain. One study even showed a surprising 62% higher death rate in the cohort that consumed safflower oil and margarine compared to olive oil and butter.
As if the health implications of vegetable oils shown in studies weren’t bad enough, it’s also a fact that between 85-90% of conventional soybean, corn, cotton, and canola oils are grown from GMO seeds. Besides the possibility that GMO seeds are toxic in and of themselves, GMO seeds tend to be resistant to herbicides, causing farmers to spray excessive amounts. Herbicides are known to negatively affect the gut microbiome, welcoming an array of health issues.
Many studies have shown that vegetable oils are likely to cause a wide range of health issues including cardiovascular disease, type 2 diabetes, and even cancer. Considering the health implications of vegetable oils, it’s clear that the push on vegetable oils being a “healthy'' choice is in need of a serious revaluation. The idea that vegetable oils are healthier than saturated fats like butter is based on a hypothesis that has been refuted by many.
Though many professionals today still continue to push vegetable oils as a healthier replacement for saturated fats, it should be taken into consideration that humans have consumed mainly saturated animal fats without any issues for thousands of years prior to the rise in obesity and chronic illness, while vegetable oils are still fairly new to the human diet. It’s time we stop villainizing what’s always been a part of the diet and start questioning what was never in the human diet to begin with.
Love Evie? Let us know what you love and what else you want to see from us in the official Evie reader survey.