The first research papers showing the dietary dangers of trans fats were published in the 1960s. Yet they were mostly ignored, as influential scientists who happened to work for food manufacturing companies wrote rebuttals against the papers’ claims.
The first study that did have an impact was conducted in 1994 by a researcher named Joseph Judd. In his study, participants consumed a diet either high in olive oil, high in trans fats or moderate in trans fats. Interestingly, Judd found that a diet high in trans fats caused a rise in cholesterol levels.
Following this study, people more and more began to oppose the use of trans fats in processed foods, and they were even banned in some cities and states in the United States. Food manufacturers now had to find another fat replacement. Unfortunately, the choices they made were still dangerous to our health. There are a few possible alternatives to trans fats. Some food makers returned to palm oil – often used for baked goods or potato chips – which they’d used before trans fats were introduced in the 1980s.
Other companies experimented with genetically engineered soybeans. Soybeans have some good health characteristics, such as being high in oleic acids, which are also found in olive oil. Ultimately, genetically engineered soybeans weren’t a viable option as beans were in short supply.
Some manufacturers tried to use liquid vegetable oils, such as sunflower oil. Vegetable oils are useful for fried products, but they couldn’t be used in most packaged foods as they go rancid too easily.
Even using vegetable oil for frying can have serious consequences. In 2007, for example, fast food chain McDonald’s started using vegetable oil in its fryers, believing it was a healthier choice. However, when vegetable oils are heated, they can create dangerous substances called toxic breakdown products.
One especially dangerous toxic breakdown product called aldehyde can interfere with your DNA. Aldehyde is also very chemically reactive, which means it can interact with chemicals in your body and potentially destroy your cells. Consuming foods fried in vegetable oils under certain circumstances could increase your chances of getting cancer. So food producers found themselves back at square one: saturated fats were bad, but trans fats were worse. And to boot, even seemingly healthy vegetable oils could pose health problems.
While Keys’s diet-heart hypothesis was widely accepted, not everyone was convinced by it. Some studies did question its premise, yet few paid much attention to the counter-arguments. One study in the 1950s had participants eat a diet that cut back on red meat, which itself is high in saturated fat. Much later, in 1962, the New York Times published the study’s preliminary results.
It suggested that eating red meat was not as unhealthy as previously thought. The eating habits of a Kenyan tribe called the Masai also countered Keys’s diet-heart hypothesis. Some 60 percent of the total calories a tribal individual consumes comes from foodstuffs high in saturated fats: meat, blood and milk.
Inundated with messages from trusted sources that saturated fat is dangerous, many parents made sure their children ate a low-fat diet. The diet-heart hypothesis was so widely accepted that many Americans changed their buying habits. Between 1970 and 1997, the consumption of whole milk dropped from 214 pounds per person per year to 73 pounds. At the same time, the consumption of low-fat milk increased from 14 pounds per person per year to 124 pounds.
So a diet low in saturated fats seems to affect women and children differently. But why? It turns out that there are different types of cholesterol, and not all of them are bad. Keys’s diet-heart hypothesis was popular in part as it was so simple and easy to understand. However, it turned out to be a little too simple. The diet-heart hypothesis warned against cholesterol, but didn’t differentiate between the two kinds of cholesterol.
The two kinds of cholesterol are characterized by the density of their carriers, or lipoproteins. These carriers help cholesterol travel through your veins and arteries. There are high-density lipoproteins (HDL) and low-density lipoproteins (LDL). HDLs carry HDL-cholesterol, while LDLs carry LDL-cholesterol.
Researchers found that high levels of LDL-cholesterol were associated with people who smoked, were overweight, didn’t exercise and had high blood pressure, while HDL-cholesterol was associated with just the opposite: people who exercised, didn’t smoke and had a healthy body weight.
Thus, LDL-cholesterol was dubbed “bad” cholesterol and HDL-cholesterol was “good” cholesterol. There is some truth to these labels. LDLs fix cholesterol into the walls of our arteries, whereas HDLs clear the cholesterol out of our arteries.
Studies have actually suggested that HDL-cholesterol helps to fight heart disease. In a follow up of the Framingham Study, researchers found that low levels of HDL-cholesterol were directly associated with heart attacks.
In fact, the rate of heart attacks among people with low HDL-cholesterol was eight times higher than the rate of people with high HDL-cholesterol. Raising your level of HDL-cholesterol is actually the best way to combat heart disease. However, many influential organizations, like the AHA, advocate instead for lowering your LDL-cholesterol levels, which is not as effective.
The two types of cholesterol have very different effects, and it’s important to understand these differences. There is a reason HDL-cholesterol is “good” and LDL-cholesterol is “bad.” Since the primary focus in the 1980s was on lowering LDL-cholesterol, many popular diets focused on that aspect. Olive oil was thought to lower LDL-cholesterol, which is why the Mediterranean Diet became popular.
Researchers pointed to what became known as the Mediterranean Diet as a way to help combat heart disease. Such a diet, traditionally enjoyed by people living in Mediterranean countries such as Greece and Italy, includes high amounts of unsaturated fats, by using olive oil rather than animal fats. It also includes vegetables, fruits, nuts and lean meat.
The Mediterranean Diet is still popular, largely because of recent studies further showing the benefits of such a combination of foods. In 2008, for example, one study found that such a diet lowered participants’ LDL-cholesterol more than a diet low in carbohydrates or fats.
How else can we fight heart disease? It turns out that cutting out carbs, or foods high in starch or sugar, can help keep your heart healthy and keep you slim, too. It turns out that a diet recommending the consumption of fat instead of sugars, that is, a low-carb diet, has been around as long as 1863. That’s right: this is a diet that’s more than 150 years old!
Reducing your intake of carbohydrates – whether complex carbs such as pasta and breads or simple carbs such as desserts and candy – has been lauded for its positive effects for some time. In 1919, a physician named Blake Donaldson recommended for his patients a diet low in carbohydrates.
Not only did Donaldson’s patients in general lose weight, but also they struggled less with heart disease, gallstones and diabetes. The cardiologist Robert Atkins wrote his bestseller, Dr. Atkins’ Diet Revolution, in 1972. It was heavily criticized by the scientific community at the time as it promoted the consumption of fat, which was thought to be unhealthy.
Some researchers studied the Atkins Diet alongside the Mediterranean Diet, and concluded that the combination of the two was the most effective way to avoid heart disease. This is why diets that are relatively high in fat, like the Atkins Diet, are generally healthier than most people assume.
Diets low in carbohydrates have been proven to be beneficial, similarly as diets like the Mediterranean Diet have shown to increase “good” cholesterol and keep heart disease at bay.
It turns out that fat has an important place in a healthy diet after all! Don’t blindly avoid saturated fats! It’s actually important to eat them. Fats have a wide variety of positive effects and balanced diets that are high in “good” fats and low in carbohydrates can keep you healthy.
Check out my related post: Do you use the Four? – Part 1