Many people have assumed that fat is bad. The truth is that not all fats are bad. The type of fat and the amount of fat is what matters most. Dietary fat is essential in several metabolic and physiological functions of the body. Fat is broken down into four types, saturated, trans, monounsaturated and polyunsaturated.
Saturated and trans fats are known to be the “bad guys” and are mostly solid at room temperature such as a stick of butter. Monounsaturated and polyunsaturated fats are the “good guys” and are liquid at room temperature such as vegetable oil. Polyunsaturated fats contain two essential fatty acids, omega-3 and omega-6 that we must consume through food. Omega-3 fatty acids contain eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) which are important for proper cell function. Total fat consumed should not exceed 30-35% of daily caloric intake, and no more than 10% should come from saturated fat. For someone who consumes 2,000 calories a day, 600-700 calories would come from total fat and up to 200 calories from saturated fat.
The type and amount of fat is important for proper metabolic and physiological functions. Saturated and trans-fat can increase LDL (bad) cholesterol levels and lead to heart disease. Monounsaturated fat can lower LDL cholesterol and has anti-inflammatory effects. Polyunsaturated fats that include omega-3 (EPA and DHA) and omega-6 are required for metabolism and when consumed in an insufficient amount, can be a factor in several illnesses. In omega-3, EPA is important for general mental health and can help alleviate depression. Also in omega-3, DHA is stored in the brain and nerve cells and is important in normal brain growth, development, and maturation. DHA is also involved in communication between brain cells, genetic expression and for production of cell membranes.
Fat is an important macronutrient because it supplies the most energy (9 kcal per gram) and stores energy for later use. We need to consume fat to transport fat soluble vitamins A, D, E and K. Fat provides protection to organs and insulation to help retain body heat. Dietary fat contributes to flavor and texture of food giving salad dressings a smooth texture and ice cream a creamy texture. Finally, fat takes a longer time to digest which helps to feel full for a longer time as energy is slowly being released.
There are plentiful sources of monounsaturated and polyunsaturated fats. Sources of monounsaturated fats include but are not limited to nuts, olive oil, avocados and peanut butter. Polyunsaturated fats, especially omega-3 fatty acids, can be found in fatty fish, walnuts, canola and soy bean oil, ground flaxseed (oil), and eggs. Omega-6 can also be found in eggs and nuts, as well as poultry, whole grains and vegetable oils. It is important to note that plant sources of omega-3 do not contain EPA and DHA.
It is important to remember that not all fats are bad. Saturated and trans fats should be limited and/or replaced with mono and polyunsaturated fats. Saturated fats can lead to heart disease and stroke if consumed in high amounts. Favorite snacks that contain saturated fat should be consumed in moderation. The American Heart Association recommends dietary intake of vegetables, fruits, whole grains, low-fat dairy, poultry, fish, legumes, non-tropical oils and nuts. Also, limiting sodium, sweets, sugar sweetened beverages, and red meats will aid in reducing intake of saturated and trans fats. Moderation, variety and balance is key!
By Michele Delo
Mahan, Kathleen. L, Raymond, Janice L. Krause’s Food and the Nutrition Care Process. 14th ed. 2017, Elsevier Inc. pp. 657, 842, 1024, 1047.
Nutrition. Pearson Custom Library. pp. 110
healthyforgood.heart.org. 2017. American Heart Association.