Understanding Dietary Fat
Like protein and carbohydrates, dietary fat is a macronutrient required in relatively large amounts on a daily basis. Each macronutrient has what we call an average macronutrient distribution range (AMDR). Dietary fats have an AMDR of 20 – 35% of daily calories (carbohydrates 45 – 65% and protein 10 – 35%). This means, based on a 2,000 calorie diet, about 400 to 700 of those calories should come from dietary fat. So why do some people try to restrict dietary fat when it’s been established as an important component of a healthy diet?
Unfortunately, dietary fat is the most underappreciated macronutrient, and it is arguably also the most misunderstood. Some weight loss strategies restrict dietary fat entirely while others place greater emphasis on dietary fats to compensate for carbohydrate reduction. Fact is, dietary fat is an important part of a healthy, balanced diet – whether you are trying to lose weight or not. Regardless of your goal, it’s essential for the nutrition of all healthy adults.
Dietary Fat Facts
Dietary fats provide 9 calories per gram, more than twice that of carbohydrate and protein. With this concentrated energy, dietary fat can be used to fuel physical performance. However, dietary fats contribute far more than just energy and good food taste. They also play an important role in numerous physiological processes including supporting brain and joint function, contributing to healthy skin and hair in addition to assisting with the absorption of fat-soluble vitamins A, D, E and K. Dietary fats also have an important role in your body’s growth and development, and help form the structure of various hormones and cells.
Types of Dietary Fat
Dietary fats are also known as lipids and fatty acids. The amount of fatty acids and the number of double bonds in the chemical chain structure help to distinguish the type of dietary fat. Not all fats are created equal, but regardless of the type, each gram still provides 9 calories. Let’s take a closer look.
Saturated fats do not contain any double bonds between the carbon molecules. They are typically solid at room temperature. Saturated fats are commonly found in animal products such as meats (chicken, beef, turkey, pork), whole fatty dairy products (butter, cream, cheese) and even tropical oils (palm oil, coconut oil). You should try to minimize / limit intake of saturated fat.
Unsaturated fats contain double bonds between the carbon molecules. You may have heard of monounsaturated fats (MUFAS) or polyunsaturated fats (PUFAS). MUFAS contain one double bond whereas PUFAS contain more than one double bond. Unsaturated fats are typically liquid at room temperature and often referred to as oils. Most plant-based liquid oils are unsaturated and examples include the following: soybean oil, corn oil, olive oil, canola oil, sunflower sesame oil, peanut oil and safflower oil. Remember that although coconut oil and palm oils are liquid they are high in saturated fat. Other than oils, we can also find unsaturated fat in foods like avocados, nuts, seeds and fish.
Unsaturated fats are often referred to as healthy fats as they can potentially help reduce “bad” cholesterol (LDL) levels in your blood and raise the “good” cholesterol (HDL) which ultimately can lower your risk for heart disease and stroke. Try to increase your intake of unsaturated fats.
Cholesterol is found in every cell in your body and is a major component of nerves and the brain. It’s a building block for steroid hormones including testosterone, estrogen and progesterone. Two thirds of your cholesterol is produced by the liver. One third comes from your diet - primarily animal based foods. Although we can consume cholesterol from the foods we eat, our body also produces cholesterol daily. Serum cholesterol is often mistaken for dietary cholesterol. They are two different things.
Trans fats are created when dietary fats are chemically hydrogenated. Hydrogenation simply changes the structure of unsaturated fatty acids. Essentially, you’re adding hydrogen to a liquid which turns it into a solid. Manufacturers may hydrogenate products to extend shelf life, alter cooking properties and improve taste. Unfortunately, trans fats are linked to increased risk of cardiovascular disease. These trans fatty acids raise blood cholesterol levels more so than dietary cholesterol, saturated fats or any other type of dietary fat. Trans fats may be found in bakery products (pastries, biscuits, muffins, cakes, pies, cookies) and fried foods (French fries, doughnuts, fried chicken).
How Dietary Fats Help Fuel Performance
Dietary fats play a role in exercise and can potentially impact training. This nutrient not only provides energy, but can serve as an efficient storage form of energy. Dietary fats have a high yield of ATP (Adenosine Triphosphate) which muscles use to contract, relax and offset fatigue. After about 10 minutes of exercise, your body switches from using primarily carbohydrates for energy to a mix of carbohydrates and fats. Dietary fat is the primary fuel source for low to moderate intensity exercise.
As mentioned earlier, dietary fats should make up 20 – 35% of the calories you consume each day. Gaining a better understand of your energy needs can help you find the right macronutrient balance. Adjust as needed, but keep in mind that severely restricting dietary fat is not recommended to achieve weight loss. Athletes can adhere to a short-term, low fat diet to help achieve body composition goals, but long-term inadequate intake of dietary fat can negatively impact training and performance.