Fat is often feared for its potential to increase body weight and stored body fat. While consuming too much dietary fat can lead to obesity, fat plays many vital roles in the human body. A diet completely devoid of fat can be unhealthy and even dangerous. For some people, low-fat diets can be an effective tool in promoting weight loss. However, it is important to understand which fats should be eliminated and which fats are necessary for good health.
Importance of Dietary Fat
Essential fatty acids are fats that the body cannot produce on its own, that must be consumed through dietary sources. Essential fatty acids, along with triglycerides and cholesterol, are important for energy storage, body insulation and the protection of vital organs, including the heart, kidneys and liver. Dietary fats are also important for immune function and chemical reactions that help regulate growth, reproduction and metabolism. Certain vitamins, referred to as "fat-soluble vitamins," also require fat for absorption and storage, making fat consumption essential for good health.
Dangers of No-Fat Diets
When you completely cut fat out of your diet, your body will not be able to function in a healthy and normal way. Fats are important for brain development, blood clotting and controlling inflammation. When you consume no fat, your brain lacks the nutrients it needs to function properly, and you put yourself at risk for bleeding. Imbalances in dietary fat -- either too much or too little -- can lead to diseases, and because fats can serve as a reserve source of energy, completely eliminating dietary fats can leave you energy-deficient.
Low-Fat Diets and Weight Loss
Low-fat diets have been promoted for decades as a way to decrease the risk for heart disease and promote overall health. Harvard School of Public Health, however, notes that low-fat diets are not all they're cracked up to be. The school cites a study published in 2006 in "The Journal of the American Medical Association" that found that reduced fat intake did not significantly reduce the risk of cardiovascular disease or stroke. However, because each ounce of dietary fat contains more than twice the calories of protein or carbohydrates, reducing fat intake can significantly reduce overall calorie consumption. A study published in 2004 in "The Journal of Clinical Endocrinology and Metabolism" found that low-fat and low-carb diets were equally effective in decreasing body weight in obese adults.
Fats to Keep and Fats to Cut
Diets that are relatively low in fat can be safe, so long as you know which fats to cut and which to keep. Polyunsaturated fats contain two classes of essential fatty acids -- omega-3 and omega-6 -- that are necessary for good health. These fats can be found in fatty fish, such as trout, herring and salmon, as well as in vegetable oils, including soybean oil and corn oil. Flaxseeds and walnuts are also good sources of omega fats. Monounsaturated fat is another important type of fat that can be found in nuts, avocados, olive oil, canola oil and sunflower oil. While these unsaturated fats can lower your risk for heart disease, trans fats and saturated fats can increase your heart disease risk. Saturated fats are most commonly found in animal sources, such as fatty meats, butter, cheese and whole milk. Trans fatty acids can be found in many packaged foods and baked goods.
- National Institute of General Medical Sciences: What Do Fats Do in the Body?
- MedlinePlus: Dietary Fats Explained
- Harvard School of Public Health: Low-Fat Diet Not a Cure-All
- Journal of the American Medical Association: Low-Fat Dietary Pattern and Risk of Cardiovascular Disease: The Women's Health Initiative Randomized Controlled Dietary Modification Trial
- The Journal of Clinical Endocrinology and Metabolism: Comparison of a Low-Fat Diet to a Low-Carbohydrate Diet on Weight Loss, Body Composition, and Risk Factors for Diabetes and Cardiovascular Disease in Free-living, Overweight Men and Women
- Centers for Disease Control and Prevention: Polyunsaturated Fats and Monounsaturated Fats
- Circulation: Very Low Fat Diets