Too much of a good thing can be bad. That’s the case with eating even the healthy fats that most Americans don’t currently get enough of in their diets. The Dietary Guidelines for Americans 2010, along with other public health authorities, say you need to consume more monounsaturated and polyunsaturated fats because they are healthy for your heart. You need to be careful with all fat intake, however, because of its calorie content, but too much of these healthy fats can also pose a danger to your good health.
The Dietary Guidelines for Americans 2010 advises most people to begin replacing some of their saturated fat intake with more mono- and polyunsaturated fats, found in fish, shellfish, nuts, seeds and some oils. The health benefits of these fats are many. Harvard University’s School of Public Health says unsaturated fats improve blood cholesterol levels, lower blood pressure, reduce inflammation and stabilize heart rhythms. The University of Maryland Medical Center says some polyunsaturated fats are crucial to brain function, behavior, and normal growth and development, while the Mayo Clinic says some monounsaturated fats might improve blood sugar control and insulin levels.
All fats have nine calories per gram, making it really easy for you to consume excess calories whenever you add even these healthy fats to your foods. This puts you at risk of weight gain. Keep your portion sizes small and bear your total caloric intake in mind when you begin adding these fats to your diet. In addition, Harvard University says you might receive more health benefits when you eat these fats in place of extra carbohydrates. The Dietary Guidelines says mono- and polyunsaturated fats should replace saturated fats, so key to receiving health benefits is not simply adding these fats, but replacing unhealthy fats and compensating for total calories.
The University of Maryland Medical Center says eating too many polyunsaturated fats might increase your risk of certain cancers. The link has always been theoretical based in part on animal studies. For example, a Harvard professor publishing in the “British Medical Journal” wrote that polyunsaturated fat is prone to oxidation -- or goes rancid. This process can generate free radicals. In animals, consuming too much of this otherwise healthy fat increased the incidence of tumors. “Too much” was defined as about 5 percent of total calories, which is on par with the average amount consumed by people.
Imbalance of Omega-3 and Omega-6 Fatty Acids
Omega-3 and omega-6 are a type of polyunsaturated fats. They are considered essential in that you need them, but your body can’t make them. Omega-3s are found in fatty fish such as mackerel, lake trout, herring, sardines, albacore tuna and salmon. Most omega-6's found in the typical American diet come from vegetable oils in the form of linoleic acid. It’s important to keep a balance of these two types of fats, but most Americans tend to eat 14 to 25 percent more omega-6's than omega-3's, according to the University of Maryland Medical Center. The October 2002 issue of "Biomedicine and Pharmacotherapy" reports that this imbalance contributes to growing rates of inflammation and chronic illnesses such as heart disease.
Moderation is Key
You’ve heard it before, and it’s no less true when it comes to eating healthy fats. The Institute of Medicine recommends most American adults get 20 to 35 percent of all their daily calories as total fat. For a person following a 2,000-calorie diet, that’s roughly 44 grams to 78 grams of fat daily. Remember that the Dietary Guidelines encourages you to eat fewer than 10 percent of your calories in the form of saturated fat. Men should consume 17 grams of omega-6 fatty acids until age 50, when they need about 14 grams. Women’s figures are 12 grams and 11 grams, respectively. Adult men of all ages need about 1.6 grams of omega-3s and women need 1.1 grams.
- Harvard School of Public Health: Fats and Cholesterol: Out With the Bad, In With the Good
- University of Maryland Medical Center: Dietary Fats Explained
- British Medical Journal: Polyunsaturated Fat and the Risk of Cancer
- FitDay: How Much Polyunsaturated Fats Should You Consume?
- Biomedicine and Pharmacotherapy: The Importance of the Ratio of Omega-6/Omega-3 Fatty Acids
- Institute of Medicine: Dietary Reference Intakes: Macronutrients
- University of Maryland Medical Center: Omega-6 Fatty Acids
- University of Maryland Medical Center: Omega-3 fatty acids