You might be surprised to learn that there is a lot more to healthy fats than avocados and olive oil. In fact, healthy fats come in many different shapes, sizes, and forms, and are an integral part of a healthy diet. So here is everything that you need to know about healthy fats and the best and worst sources to include in your diet.
What is Dietary Fat?
Fat is a nutrient, along with protein and carbohydrates, which makes up the primary macronutrients of the human diet. Dietary fats are made of smaller molecules, called fatty acids, which are composed of carbon and hydrogen elements joined together in long chains called hydrocarbons. Depending on their exact structure, dietary fats have unique properties and play different roles in the human body.
Types of Fat: Saturated vs. Unsaturated Fats
There are 2 primary types of dietary fat: saturated fat and unsaturated fat, and the difference can be found in their bond structure. Although all fats are classified into these categories, it is important to understand that all fat-based foods contain a combination of different types of fat, but are classified by the type of fat they contain the most of.
Saturated fats contain no double bonds between their carbon atoms, the chain is “saturated” with hydrogens, which results in a very straight structure with molecules packed together very tightly. For this reason, saturated fats are generally solid at room temperature, which makes them great cooking fats given they are not prone to damage by heat. Saturated fats can be found in long-chain, medium-chain, and short-chain forms, all of which play different roles in the human body. Common sources of saturated fat include:
- Red meat
- Dairy products
- Animal fats
Unsaturated fats contain one or more double bonds and can be broken down into two sub-categories: monounsaturated fats and polyunsaturated fats. Depending on their bond structure, unsaturated fats have one (mono-) or more (poly-) double bonds in the chain of carbons. Given not all of the carbons have hydrogens connected to them; this puts a “kink” in the chain, which leaves unsaturated fats liquid at room temperature.
Monounsaturated fats, or MUFAs, have a single double bond in their structure. There are many different types of monounsaturated fats found in our food, with oleic acid being one of the most common. Similar to saturated fats, monounsaturated fats help to form the structural fats of the human body and are considered healthy. Monounsaturated fats are commonly known as “good fats” because they have been shown to have beneficial effects on cardiovascular disease risk markers by reducing LDL while increasing HDL, lowering triglycerides associated with heart disease and fight inflammation, and lowering blood pressure. Common sources of monounsaturated fat include:
- Some meats
- Some nuts
Unlike saturated and monounsaturated fats, polyunsaturated fats, or PUFAs, have multiple double bonds in their structure. For this reason, polyunsaturated fats are the most susceptible to oxidative damage from light, heat, and air, especially in high-heat cooking. There are two major types of polyunsaturated fats; omega-3 fatty acids which have their first double bond at the third carbon, and omega-6 fatty acids which have their first double bond at the sixth carbon. Common sources of polyunsaturated fat include:
- Fatty Fish
- Flax Seed
- Seed oils (canola, soybean, corn, safflower, etc.)
Essential Fatty Acids
Omega-3 and omega-6 fatty acids are forms of polyunsaturated fatty acids and the most well-known fatty acids given their numerous health benefits. The most important omega-3 fats include ALA, DHA, and EPA and have been shown to be particularly beneficial for heart health. Our bodies mostly use EPA and DHA, which are commonly found in cold-water fish, while the body must convert ALA, commonly found in plant sources such as flax, hemp, and chia. Although both omega-3 and omega-6 fatty acids have integral functions in the body and are essential for optimal health, they are most effective in balance. While anthropological evidence suggests that our hunter-gatherer ancestors consumed omega-6 and omega-3 fats in a ratio of roughly 1 to 1, for general health it is now recommended that they be consumed at a ratio of 4 to 1 or less.
Why Do I Need Fat?
Getting enough fat is essential for optimal health. Dietary fats are required for cellular metabolism and cell signaling; the health of various body tissues; healthy hormone function; and essential nutrition absorption of fat-soluble vitamins A, D, E, and K. Not to mention, fat is an incredibly satiating macronutrient that will help to keep you full between meals and provide delicious flavor. Generally speaking, the dietary fat that we consume is either: 1) used for energy; 2) incorporated into other body tissues and organs, or 3) stored as adipose (fat) tissues.
Are All Fats Healthy?
Although popular terminology typically classifies saturated fats as “unhealthy” fats and unsaturated fats as “healthy” fats, it’s not that simple. Humans have consumed unprocessed forms of both saturated and unsaturated fats for our entire existence given we evolved on diets consisting of marine life, wild game, milk, coconuts, and/or inland plants. Therefore, a better definition of “healthy fat” would be; unprocessed fat found in whole foods.
But, Isn’t Saturated Fat Bad for You?
In short, no, but only when you are focused on whole foods. Although conventional wisdom long held the belief that saturated fat was a health risk that is not the case, and evidence now shows that saturated fat is vital for optimal health.
The fear of saturated fat began in the 1950s when a researcher named Ancel Keys published The Seven Countries Study linking saturated fat and cholesterol with rising rates of heart disease. Prior to this study, saturated fats were consumed by humans regularly without concern; we cooked from scratch, used butter, ate whole eggs, and ate nose-to-tail cuts of meat. However, once this study was published, our perceptions of food changed. In fact, this study was the catalyst in demonizing saturated fat, which led to the increased production and consumption of low-fat and fat-free products worldwide.
With a limited understanding and knowledge of the roles of saturated fats at the time, this theory went rather undebated for many years, however, upon further research and understanding in the past decades, these findings have come under serious question. As it turns out, Key’s research was heavily flawed and the data presented was not truly representative of his findings. It has now been shown that Keys based his theory on a study of six countries, in which higher saturated fat intake equated to higher rates of heart disease, however, he conveniently ignored data from 16 other countries that did not fit his theory. Had he represented all of the countries the data would have shown that increasing the percentage of calories from fat helps to reduce the number of deaths from coronary heart disease.
In recent years, new studies have disproved the diet-heart hypothesis and debunked it many times, however, the concept that saturated fats are unhealthy and cause heart disease remains one of the largest nutritional myths that is perpetuated by mainstream media today.
From a biological perspective, humans require saturated fat because we are warm-blooded. Saturated fats are solid at room temperature and these fats provide the appropriate stiffness and structure to our cell membranes and tissues. Some of the many benefits of saturated fats include strengthening the immune system, improved brain health, improved lung health, improved liver health, and nutrient absorption.
From a chemistry perspective, it is actually the saturated nature of the bonds in saturated fats that make them ideal sources of fat for cooking given they are very stable at high temperatures. On the contrary, since unsaturated fats do not contain double bonds and their structures are therefore not “saturated”, they are less than ideal for heating and cooking as they are very susceptible to oxidation and rancidity.
Moreover, it is important to keep in mind that humans evolved eating wild game, marine life, and plant life, and have consumed unprocessed forms of saturated fats (organ meats, blubber, milk, or coconuts) for our entire existence. In fact, current tribes from around the world still consume diets high in saturated fats; Eskimo tribes consume native diets with up to 75% saturated fats, the Maasai Tribe in Kenya consumes a diet with up to 66% saturated fat, and Tokealu of New Zealand consume a diet of 60% saturated fat with virtually no heart disease.
So, is saturated fat a healthy fat? Yes, but only when you focus on saturated fats from whole foods in their whole formats.
So, What Are “Unhealthy Fats”?
Although saturated fats are often described as “bad” fat or “unhealthy” fats, that is not the case. Unhealthy fats are in fact fats that are industrially produced and designed to be non-perishable, which include:
- Trans-fatty acids,
- Hydrogenated fats,
- Most shelf-stable cooking oils.
Trans fats and hydrogenated fats are commonly found in processed food and are often considered man-made fats. Although there are small amounts of trans fats naturally occurring in meat and dairy products, it is artificial trans fats that are considered dangerous. Artificial trans fats have been shown to create inflammation and contribute to a number of detrimental health conditions. Trans fats and hydrogenated fats are commonly found in commercial baked goods, margarine, and some fried foods.
In addition to trans fats and hydrogenated fats, shelf-stable cooking oils should also be considered unhealthy fats. Although vegetable oils have been touted as “heart-healthy” and we have been encouraged to use them in place of saturated fats such as butter, they are in fact a less-than-desirable form of cooking oil. The term vegetable oil is used for oils that have been extracted from seeds including canola oil, corn oil, soy oil, rapeseed oil, and safflower oil, and is actually used as a blanket term for these oils. In fact, when you buy “vegetable oil” at the grocery store you are often buying a combination of these seed oils. Unfortunately, the term “vegetable oil “is simply used to imply that the oils are not made of animal fats. Although the word vegetable is often associated with health, vegetable oils are anything but, it just happens to be good marketing.
The first and most obvious concern with vegetable oils is simply that these oils are not fit for human consumption. Unlike natural fats, vegetable oils can’t be extracted by pressing or separating, these oils require extensive processing to extract their oils. The process of creating vegetable oils involves chemical extraction, degumming, refining, bleaching, and deodorizing, making them a highly processed form of oil.
The second concern with vegetable oils is their high content of polyunsaturated fatty acids, also known as PUFAs. As noted early, polyunsaturated fats are highly unstable and oxidize very easily. Omega-6s are the PUFAs specifically found in vegetable oils, and although they are essential to human health, in excess they are dangerous and inflammatory. The ideal ratio of consumption of omega-6 to omega-3 fatty acids is somewhere in the range of 1:1 to 4:1, however, that ratio has increased as high as 10:1 or 20:1 in the Standard American Diet, due in large part to the consumption of vegetable oils and products that contain them.
Another concern with vegetable oils is how fragile and easily damaged they are by exposure to light, heat, and air. Unfortunately, that is exactly how they are used and exposed in most grocery stores, households, and restaurants. Not only are they often found in clear bottles and stored in warm areas near stovetops, but they are also commonly used in deep fryers and sauté pans all over the world.
And finally, since vegetable oils are chemically produced it will likely not come as a surprise that they are full of chemicals. Vegetable oils, specifically vegetable oil products such as margarine, often contain added preservatives, emulsifiers, colors, flavors, and sodium.
Although some products will simply be labeled as “vegetable oil”, some might be found under more specific names, but they should all be limited. Common forms of vegetable oil include:
- Canola Oil
- Corn Oil
- Cottonseed Oil
- Grapeseed Oil
- Rapeseed Oil
- Soybean Oil
- Safflower Oil
- “Vegetable” oil
- Fake butter or spreads
So, What Fats Are “Healthy Fats”?
Healthy fats are those found in their natural form in whole foods and can be found in the form of saturated fats, polyunsaturated fats, and monounsaturated fats. Healthy fats are minimally processed and responsible for many important functions in the body; they serve as a source of energy; help to absorb fat-soluble vitamins; support cell formation and structure; regulate temperature and are vitally important for brain function the nervous system and hormone development. Moreover, since natural dietary fats are so energy and calorie-dense, they can help to manage hunger cues, balance blood sugar and minimize cravings by providing a lot of energy in a small bite.
The Bottom Line
Healthy fats are integral for overall health and by eating a wide variety of fat-based whole foods, such as high-quality animal meats, animal fats, fish, seafood, eggs, olives, avocado, nuts, and seeds, you can help to ensure that you are consuming a good balance of healthy fats. When cooking at home, avoid using vegetable oils and sprays, instead opt for natural oils such as butter, ghee, olive oil, avocado oil, or coconut oil, and store the liquid oils in dark bottles away from heat sources.