Despite their bad reputation, lipids -- fats and fatlike substances -- play a crucial role in your health. The problem is that many Americans eat too much fat and too much of the wrong kinds of fat, which leads to problems like high triglycerides, elevated cholesterol and weight gain. You should limit your intake of fat to 20 to 35 percent of your total calories, and the bulk should come from healthy fats.
At the most basic level, fat serves as a source of stored energy. Eating foods that contain fat helps slow digestion and contributes to a feeling of fullness after eating. Fat is also needed for your body to absorb the fat-soluble vitamins A, D, E and K. Stored fat helps insulate you and protect your organs by acting as a cushion. In addition, your body uses fat to produce hormones and to help regular communication between cells, also known as cell signaling. Cell membranes and nerve fibers require lipids as part of their structure in order to function properly.
Dietary saturated fat is referred to as "bad" because it raises the level of LDL in your blood, a form of cholesterol that conributes to heart disease. For this reason, eating too much saturated fat puts your heart health at risk. You find saturated fat in many foods like fatty beef, whole-fat dairy foods, processed meats and fried foods. Fats that are better for you are unsaturated -- polyunsaturated and monounsatured. When eaten in moderation, unsaturated fats help protect against heart disease. They're found in nut and seed oils, vegetable oil and fish such as salmon, mackerel and herring.
Linoleic acid and alpha-linolenic acid are the two essential fats that you must get from your diet to maintain health. LA is an omega-6 polyunsaturated fat, and ALA is an omega-3 polyunsatured fat. Your body converts ALA to EPA and DHA, two omega-3 fats linked to heart health. However, the body is not very efficient at conversion, so you should get EPA and DHA from additional sources such as fatty fish. The daily recommended intake of LA is 11 grams for women and 14 grams for men, while the recommended intake of ALA is set at 1.1 grams for women and 1.6 grams for men.
Cut back on saturated fats and replace them with foods that contain the unsaturated variety. An easy way to cut back is to swap some of your weekly beef meals for skinless chicken and fish and replace lard and butter with olive oil, flaxseed, peanut, sesame, walnut and canola oil. Another simple change is to swap whole-fat dairy for reduced-fat and fat-free options. In addition, cut back on fatty meats like sausages, hot dogs and bacon and instead choose fresh lean cuts like loin and round.
- Institute of Medicine: Dietary Reference Intakes for Energy, Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol, Protein, and Amino Acids
- University of Arizona: Fats and Cholesterol in the Diet
- Institute of Medicine: Dietary Reference Intakes -- Macronutrients
- Linus Pauling Institute: Essential Fatty Acids
- American Heart Association: Saturated Fat