Physicians have long advised patients to reduce their fat intake, due to its association with heart disease and stroke. The reality is, though, that fat has some essential benefits and there are different types of fat, some more beneficial than others.
It can absorb certain vitamins and even improve brain development. “So, is fat good or bad? According to the latest evidence, it depends a lot on the kind of fat we eat,” according to Stephen Devries, MD, a preventive cardiologist and executive director of the nonprofit Gaples Institute in Chicago.
Dr. Devries, who is a member of the American Medical Association (AMA), developed a free nutrition course available on the Gaples website that answers four critical questions about dietary fat. Areas of learning address the properties of various fats and their impact on health, as well as choosing the healthiest oils to cook under high temperature. Read to see if you’re up to speed on the role of dietary fat.
Gaples Institute nutrition and lifestyle education also is available as CME for physicians at the AMA Ed Hub™.
What role does cholesterol play in dietary fat?
Cholesterol, produced by the liver, serves essential bodily functions such as making hormones. We also ingest cholesterol through what we eat. That having been said, dietary intake of saturated and trans fats should be minimized as it elevates low-density lipoprotein LDL ("bad") cholesterol, said Dr. Devries.
People get cholesterol from food, although the body automatically produces all the cholesterol a person needs. Eggs are the largest source of cholesterol in the American diets, but beef, chicken and cheese are also high in cholesterol.
When doctors check cholesterol levels, they often measure LDL, a type of cholesterol that collects in blood vessel walls, causing blockages. High-density lipoprotein (HDL) is the “good” cholesterol that helps remove blockages and lowers cardiovascular risk.
Some reports claim that eating foods with cholesterol isn’t as risky as previously believed. This doesn’t mean you can eat all the eggs you want, cautioned Dr. Devries.
“Cholesterol in our food does cause our body's LDL or bad cholesterol to rise—not by a lot, but it's still significant,” he said.
Bottom line: It's a good idea to eat as little dietary cholesterol as possible, he advised. This is especially true for patients with type 2 diabetes, as foods with cholesterol can increase the risk of heart disease for this population.
Learn more about what doctors want patients to know about healthy eating.
What types of fats can cut the risk of heart disease?
Monounsaturated fats are found in foods such as olives, olive oil, almonds and avocados. “Of all the fats, monounsaturated are one of the shining stars,” said Dr. Devries. The Mediterranean-style diet, for example, acquires much of its benefits from monounsaturated fats.
Medical studies have shown that patients who follow the Mediterranean diet to replace saturated fat will cut their risk of heart disease. Watch this AMA video to learn more about which dietary patterns are best for weight loss.
Olive oil is a well-known, delicious source of monounsaturated fat. Dr. Devries recommended that people choose extra virgin olive oil, which has a higher content of polyphenols. These plant-based compounds have antioxidant and anti-inflammatory properties and are known to increase HDL.
Another useful fat is polyunsaturated fat, which is found in several types of plant oils, walnuts, flax and fatty fish such as salmon. People who replace foods that are high in saturated fat, like meat and cheese, with foods that have healthier fats often experience significant health benefits.
“You've probably heard of omega-3 and omega-6. These fatty acids are both part of the family of polyunsaturated fats. They're called essential fatty acids because our bodies can't make them on their own. We have to get them from the foods we eat,” Dr. Devries explained.
Several common food ingredients are loaded with omega-6 fats, such as soybean oil, seed oils and corn oil. Omega-3 is not as prevalent. However, it can be found in fish such as salmon, sardines and halibut, as well as plant sources, including walnuts, flax and chia.
What are the most dangerous types of fats?
Saturated fats from meat, dairy, coconut oil and palm oil lead to arterial plaque buildup even in young people. People should substitute them with whole grains, vegetables or polyunsaturated fats.
Trans fats are the most hazardous type of fat. They raise LDL, lower HDL and can trigger inflammation, which plays a key role in many chronic diseases.
For a long time, trans fats were a key ingredient in processed foods and fried foods. Fortunately, recent FDA regulation has essentially eliminated artificial trans fats from the food supply.
What kinds of fats should I choose to cook with?
The Gaples Institute module also discusses which fats are best for cooking. “The kind of fat you choose to cook with can be really important because not all cooking oils are safe to consume if they're heated to very high temperatures,” said Dr. Devries.
Each oil has a unique temperature at which it begins to smoke, called the “smoke point.” If you heat oil to its smoke point, it begins to degrade into potentially carcinogenic chemicals.
Dr. Devries outlined some “important rules of thumb” in cooking with fats. For sauteing, use extra virgin olive oil. Just don't turn the heat up all the way, and limit the cooking time.
For higher-temperature cooking or prolonged cooking, consider grape seed or avocado oil, which have higher smoke points. Avoid heating oil to the point that it begins to smoke.
“But if oil does get heated to the point of smoking, don't use it for cooking. Get rid of it,” he advised.
Patients looking for more information on nutrition can access the Gaples lifestyle library to learn more about dietary supplements, medications, physical activity and the connection between mental and physical health.
