Dietary fats are one of the four macronutrients, or parts of our diet we need to survive, among carbohydrates, proteins and water. Fats, unlike carbs and protein, contain nine calories per gram, which is partly why they have a bad reputation. Both carbs and protein contain four calories per gram, which is significantly less than fat. So, while dietary fats are more energy-dense, they also serve many functions including hormone balance, organ and cell protection, as well as help keep us insulated (1). Just as we learned with carbohydrates, not all fats are created equal. Let’s look at the different types.
Types of fat
There are several types of fats, or lipids as they are sometimes referred to. There is saturated fat, trans fat, monounsaturated fat, and polyunsaturated fat. Structurally, each of these fats are different giving them unique characteristics. In turn, they are digested differently and serve functions based on the chemical structure. When a fat is labeled “saturated” it means that it is mostly saturated, but also contains smaller amounts of poly, and unsaturated fats. Conversely, when a fat is labeled “unsaturated,” it means that it is comprised of mostly unsaturated bonds.
Structure of fats
Saturated fats have chemical bonds that are, well, saturated. Think butter, and cheese, or a juicy steak where you can visibly see the marbling of fat; mostly products from animals. This also includes coconut oil, which is also solid at room temperature. Unsaturated fats, including mono and poly unsaturated, have a different carbon chain containing fewer hydrogen atoms, hence the name, unsaturated. These come from plant sources. Think about the nature of most vegetable oils, including olive oil, soybean oil, and other plant oils; they are liquid even on a cold day on your kitchen counter or in your pantry. This is due to the chemical structure. It might be harder to picture a trans-fat, as these are not natural fats. They are manufactured by taking a liquid and making it solid; think margarine or shortening. Typically, these are found in packaged foods to increase shelf life and enhance products.
Saturated and Trans fat
Although we need fat for many important functions, it is important to know how much you are getting and what type you are consuming. Like added sugars, it is recommended to limit your saturated fat intake to less than 10% of your total daily calories (2). This is because saturated fat increases your risk for heart disease and contributes to unhealthy cholesterol levels, or LDL levels (you want to keep those low), while also lowering your beneficial cholesterol levels, or HDL (you want to keep those high.) An easy way to remember this is LDL starts with the letter “L,” and HDL starts with the letter “H.” “L” for low and “H” for high.
Unfortunately, trans fats are not recognized as safe, although they are still present in a good amount of food products. It is known that they increase your risk of developing stroke and heart disease as well as type 2 diabetes. A way to recognize these fats are by looking on your food label for the term “hydrogenated vegetable oil.” It is recommended to cut back on foods containing these oils (3). I would recommend cutting them completely out of your diet, but that is unrealistic for many.
Poly and Unsaturated fat
While the previous fats discussed have negative effects on your cholesterol, poly and unsaturated fats actually have positive effects on your cholesterol levels. They contain omega fatty acids contributing to lowering your bad cholesterol, or LDL while increasing your HDL. They include olive oils, natural vegetable oils, nuts, seeds, avocados and fish oils. Rich in EPA and DHA, which are critical for development as well as weight management, cognitive health and coronary proficiency, these fats are more than beneficial (4). For most of us, we are not consuming enough of these healthy fats. Our dietary fat intake is predominately from saturated or trans-fats, instead of the omega-rich mono and poly unsaturated fats.
How to balance your fat intake
There are little ways you can improve the balance of healthy fats in your diet. When I say this, I mean increase your intake of heart healthy fats, which include mono and polyunsaturated fats while also decreasing your intake of saturated and trans-fat. Instead of cooking with butter you can switch to olive or avocado oil, which has a higher smoke point than other oils. If that sounds daunting, cut your butter or margarine in half and add a teaspoon of oil instead. You can add homemade dressings and sauces to your meals instead of those hydrogenated store-bought bottles with trans-fat. Add some trail mix to your snack repertoire. And try fish on the menu one or two nights a week. It’s all a matter of tipping the scales in your favor!
By: Erin Engle, M.S., Nutritionist