The Three Types of Fats In Your Food

Contributing Author: The Tortoise

Fats. They are one of the main reasons many foods taste so good. And some fats taste better than others, making it even more difficult to say no to certain foods. Fast food french fries, for example, were often cooked in lard or beef tallow before the nineties, giving them a markedly richer taste compared to fries cooked in vegetable oil¹. But all fats are not equal. And not all fats are good for us. Indeed, some of the tastiest fats may be some of the worst for our health. How do we know the difference?

Dietary fats fall into three categories: saturated fats, unsaturated fats and trans fats. We will examine each of these in turn.

Saturated Fats

Animals are the primary source of saturated fats. High levels are found in beef, pork, lamb and goat meat, and full-fat dairy products. The saturated fat levels in beef fat is 50%², lard 39%³, and butter 64%⁴. Poultry and eggs contain medium levels, with chicken fat consisting of 30% saturated⁵. Some vegetable oils, such as coconut oil and palm oil, are also very high in saturated fat, containing 82% and 49.3% respectively⁶. Saturated fats remain solid at room temperature. They should be eaten in small amounts, no more than 5 to 6 percent of your total calories. For someone eating 2000 calories a day, that equates to 11 to 13 grams of saturated fat⁷. Eating high levels of saturated fat increases LDL ('bad' cholesterol) and triglyceride levels (a type of fat converted from excess calories and stored in the fat cells), raises your blood pressure, and narrows your blood vessels⁸. All of these effects on your body increase your risk of cardiovascular disease.

Unsaturated Fats

These 'good' fats should form the majority of your fat intake as part of a heart-healthy diet. Unsaturated fats come in two types: monounsaturated and polyunsaturated. Plant-based liquid oils such as olive oil, canola oil, peanut oil, sunflower oil and sesame oil are high in monounsaturated fats, also known as oleic acid⁹. Many seeds and nuts contain good concentrations of oleic acid, including pecans, hazelnuts, almonds, sesame seeds and pumpkin seeds¹⁰. One fruit high in monounsaturated fat is the avocado. While the avocado and coconut have the highest fat contents of any fruit in the world, the fat in an avocado is mostly unsaturated, unlike the coconut's. 100 grams of raw Hass avocado contains 2 grams of saturated fat and 13 grams of unsaturated fat, of which 9.8 grams is monounsaturated¹¹. Polyunsaturated fats are the second type of unsaturated fat which is beneficial to the body, and can be found in oily fish such as salmon, mackerel, herring, tuna and trout, as well as in soyabeans and tofu, canola, walnuts, flax and sunflower seeds and their oils¹². Replacing saturated fats with unsaturated fats have been shown to lower blood pressure, improve lipid levels, decrease LDL and increase HDL ('good' cholesterol), and reduce cardiovascular risks¹³. Studies also suggest that eating good fats may decrease the risk of type-2 diabetes.¹⁴

Trans Fats

Of the three types of fats, trans fat is considered to be the worst type of fat you can eat. Also known as trans-fatty acids, trans fat raises your "bad" (LDL) cholesterol while it lowers your "good" (HDL) cholesterol, a combination which increases your risk of heart disease¹⁵. But what is trans fat? While trans fat occurs naturally in small amounts in some meat and dairy products, most trans fat is produced through an industrial process which adds hydrogen to vegetable oil, causing the oil to become solid at room temperature. This partially-hydrogenated oil is less likely to spoil, so foods made with trans fat have a longer shelf life. Manufactured trans fat may be found in baked goods containing shortening, such as cakes, cookies, pies and crackers, ready-made frosting, snack foods such as microwave popcorn, non-dairy creamers, margarines and any foods cooked or fried in partially-hydrogenated oil¹⁶. Trans fat, particularly the manufactured variety, appears to have no known benefit, with the US Food and Drug Administration (FDA) determining that partially-hydrogenated vegetable oil is no longer "generally recognized as safe" and should be phased out of food production within the next few years.¹⁷

References
¹ Palmer, Katie M., "What exactly is in McDonald's famous french fries?", Wired, July 16, 2014
² "Making Sense of Food: Types of Fat", NutritionMD
³ "Making Sense of Food: Types of Fat", NutritionMD
⁴ "Ask the doctor: Coconut oil", Harvard Health Publications
⁵ "Making Sense of Food: Types of Fat", NutritionMD
⁶ United States Department of Agriculture, National Nutrient Database, "Oil, Coconut", and "Oil, Palm"
⁷ "Know Your Fats", American Heart Association
⁸ Roberts, Eleanor., "Good Fats, Bad Fats", www.everydayhealth.com
⁹ "Monounsaturated Fats", American Heart Association
¹⁰ Roberts, Eleanor., "Good Fats, Bad Fats", www.everydayhealth.com
¹¹ "How Many Grams of Fat Are in Avocados?", Livestrong.com
¹² "Polyunsaturated Fats", American Heart Association
¹³ Roberts, Eleanor., "Good Fats, Bad Fats", www.everydayhealth.com
¹⁴ "Dietary Fats: Know which types to choose", Mayo Clinic
¹⁵ "Trans fat is double trouble for your heart health", Mayo Clinic
¹⁶ "Trans fat is double trouble for your heart health", Mayo Clinic
¹⁷ "Trans fat is double trouble for your heart health", Mayo Clinic

Photos from Morguefile.com.