Dietary Fat: The Good, The Bad, and The Yummy

Dietary fat has been a hot topic in nutrition for a long time. Should you eat fat? Is fat bad for you? Will eating fat make you fat? There’s a lot to consider, and it’s easy to become confused.

The truth is that dietary fat is a necessary part of a healthy diet, but not all fats are created equal. Read on to learn about why we need fat, the different types of dietary fat, and in what foods you can find them.

Fat is one of the three macronutrients, along with protein and carbohydrates, which means that it’s required in the human diet. The body needs fat to survive and thrive. Fat helps with absorption of some vitamins, it assists the brain and nervous system in functioning properly, it’s required for healthy hormone production, it protects internal organs, and it helps to maintain healthy skin and keep the body warm. It’s becoming increasingly understood that adopting a low-fat diet is not necessarily the way to achieve health, and part of the reason is because of all of the important functions of fat.

That said, not all fats are created equal. Some dietary fats promote health, and some contribute to disease. Below is a breakdown of several types of fat. After reading, you’ll have gained some knowledge about which fats will help you live a healthier life, and which ones you may want to limit. Trans fats are often used to give certain foods a desirable taste and texture. They are most commonly found in packaged baked goods, e.g. pies, cakes, donuts, and cookies, and they’re also found in some fried foods. On a food label, trans fats typically go by the name partially hydrogenated oil. Trans fats are problematic in that they lower “good” cholesterol (HDL) while raising “bad” cholesterol (LDL). They are known to increase the risk of developing heart disease, stroke, and diabetes. It is recommended to drastically decrease intake of these fats, or to eliminate them completely. Scanning food labels for the words ‘partially hydrogenated’ is a good way to start identifying trans fat.

Saturated fats are typically solid at room temperature. They most commonly come from animal products, such as dairy and meat. Think butter, or that nice marbling in your favorite rib-eye steak. Excess saturated fat in the diet has been linked to high cholesterol but can be eaten in moderation. Coconut oil is a plant-based type of saturated fat and is known to have health-promoting properties; it can be used in place of butter when sautéing or baking.

Monounsaturated fats are considered “good fats” and are liquid at room temperature. They’re known to be heart-healthy and are found in olive oil, most nuts, and avocados. They’re also found in peanut and sunflower oils, though it is recommended to prioritize eating whole foods versus oils, i.e. it would be better to choose a handful of peanuts than to eat something fried in peanut oil. Again, moderation is key.

Polyunsaturated fats are also considered “good fats” and are liquid at room temperature. They contain essential fatty acids, which the body cannot produce and therefore has to receive from the diet. The two types of essential fatty acids are omega-3 and omega-6. Fatty fish such as salmon, mackerel, tuna, and sardines are good sources of omega-3 fatty acids, as are walnuts, flaxseeds, chia seeds, and hemp seeds. Omega-6 fatty acids are found in vegetable oils, such as sunflower, canola, safflower, and corn oil. Note: the standard American diet generally contains adequate amounts of omega-6 fatty acids and is lacking in omega-3s. Stay tuned for a post highlighting the importance of omega-3 fatty acids in the diet.

This post only scratches the surface of dietary fat, but know this: dietary fat is necessary, but not all fats are created equal. On the road, healthy fats can be found in convenience foods like unsalted nuts and seeds, nut butters such as almond and peanut butter, and canned tuna. Olive oil can be used as a healthy alternative to vegetable oils when cooking, and it’s best to limit fried foods and packaged baked goods. Above all, remember that variety and moderation are key: don’t go on a low-fat diet, but don’t have that rib-eye every day either.


This post was written in large part by Taylor Beard, dietetic intern at Missouri State University in Springfield, Missouri. Taylor will be eligible to become a Registered Dietitian Nutritionist in May of 2018.