By Sandra Vasquez, R.D., L.D.N.
There has long been a misconception that eating fat makes you fat. But that’s simply not the case. In fact, your body actually needs fat to function properly.
Fats are an important part of a healthy diet because they provide essential fatty acids, keep your skin soft, deliver fat-soluble vitamins, and are a great source of energizing fuel. But, not all fat is created equally – there are good and bad fats and recommended amounts we should be eating, but not exceeding.
Total fat intake of 20% to 35% of energy is recommended by the Institute of Medicine and the Food and Agriculture Organization of the United Nations and is supported by the 2010 Dietary Guidelines for Americans. The American Heart Association and National Cholesterol Education Program recommend 25% to 35% of daily calories from fat. Achieving intake of total fat within the recommended range (20% to 35%) is an important goal, but the quality of fat in the diet is equally important to reducing health risk.
What Are “Good” Fats?
One of the “good” fats is monounsaturated fatty acids (MUFAs), which can be found in plant foods like nuts, avocados, olive oil and canola oil as well as in poultry. This type of fat can lower cholesterol levels, which can also lower your risk of heart disease.
Another good fat is polyunsaturated fatty acids (PUFAs), which can be found in fatty fish such as salmon and mackerel, and corn and soybean oils. PUFAs, like MUFAs, have been shown to improve cholesterol levels and reduce your risk of heart disease. One type of PUFA you have probably heard of is omega-3 fatty acid. For majority of Americans, we eat too few sources of omega-3 fatty acids – cold water fish such as salmon, sardines, herring, mackerel, black cod, and bluefish or vegetarian sources such as walnuts and flaxseeds. By contrast, sources of omega-6 fatty acids are abundant in our diets. They are found in safflower, corn, cottonseed, and soybean oils. Based on recent literature, increasing consumption of PUFAs with a particular focus on increasing n-3 intake (striving to consume two or more servings of fatty fish per) is desirable.
What Are “Bad” Fats?
Saturated fat is another type of fat found primarily from animal sources, including meats, eggs, and butter, or from processed food products containing naturally saturated vegetable oils. The AHA’s Diet and Lifestyle Recommendations (2006) recommended SFA intake be <7% of calories (approximately 16 g based on a 2,000 kcal diet) for the general population for cardiovascular disease risk reduction.
The bad fat you should avoid at all costs is trans fat, which is in some fried foods, shortening, and packaged snacks like crackers and desserts. A few years ago, artificial trans fat was banned from restaurants in a handful of cities. Research has found that the artificial kind, which is in partially hydrogenated vegetable oil, can raise your levels of bad cholesterol and lower your levels of healthy cholesterol, which is a combination that increases your risk of heart attack and stroke.
However, partially hydrogenated oil remains a rather common ingredient in processed foods. Food manufacturers use it largely because it gives food a longer shelf life. The best way to avoid bad trans fat is by cutting down on the amount of processed foods, commercial snacks and fast food you eat.
But even if you’re only eating healthy fats, you still need to watch how much you’re eating. Fat is high in calories and small amounts can add up quickly – fat has about nine calories per gram. If you eat more calories than you need, you will gain weight. Cutting the total amount of fat in your diet can help you shed pounds and better control your weight.
- US Department of Health and Human Services, US Department of Agriculture. Dietary Guidelines for Americans 2010.
- Food and Nutrition Board Institute of Medicine: Dietary Reference Intakes for Energy, Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol, Protein, and Amino Acids. Dietary Fats: Total Fat and Fatty Acids. National Academies Press. Washington, DC, 2005.
- Lichtenstein A.H., Appel L.J.American Heart Association Nutrition Committee, et al: Diet and lifestyle recommendations revision 2006: A scientific statement from the American Heart Association nutrition committee. Circulation 114. (1): 82-96.2006;
- National Cholesterol Education Program (NCEP) Expert Panel on Detection, Evaluation, and Treatment of High Blood Cholesterol in Adults (Adult Treatment Panel III): Third report of the National Cholesterol Education Program (NCEP) Expert Panel on Detection, Evaluation, and Treatment of High Blood Cholesterol in Adults (Adult Treatment Panel III) final report. Circulation 106. (25): 3143-3421. 2002.
- Vannice G, Rasmussen H. Position of the Academy of Nutrition and Dietetics: Dietary Fatty Acids for Healthy Adults. Journal Of The Academy Of Nutrition & Dietetics [serial online]. 2014;114(1):136-153.