Essentials of Nutrition Series: Fats

Posted March 29, 2010 by

In continuing our discussion of the three macronutrients contained in food (protein, carbohydrates and fat), let’s discuss the third and final macronutrient, fat. Dietary fat, like carbohydrates, is often misunderstood because people associate it with body fat and weight gain, but the truth is that in moderation (10-30% of our daily intake), fat is an essential part of our diet and is even required to live! Body fat is the physical result of our bodies storing excess calories for future energy needs, regardless of where those calories come from. Thus, one can just as easily gain body fat from the overconsumption of carbs, protein or fat, if the total calories consumed is higher than the daily expenditure.

In nature, fats come in three varieties: monounsaturated, polyunsaturated and saturated fats. Monounsaturated (commonly found in nuts, seeds and certain types of oils) and polyunsaturated (commonly found in vegetable oils and fish) fat intake is encouraged because it has been shown to lower the risk of heart disease by blood’s “bad” cholesterol (LDL). A subtype of polyunsaturated fats known as Omega-3 fatty acids (commonly found in fish and flaxseed) have been additionally shown to lower blood pressure and may even protect against irregular heartbeats. Saturated fat (commonly found in animal products and tropical oils) on the other hand, should be limited because unlike the other two varieties, it has been shown to raise “bad” cholesterol.

There is an additional type of fat that is not found in nature called trans fat. This is a man-made product that used by many fast-food restaurants and in many pre-packaged baked goods and deep-fried foods. Essentially, a healthy vegetable oil (which is liquid at room temperature) undergoes a process called hydrogenation in order to cause it to solidify at room temperature, typically for a combination of storage and food texture purposes. Unfortunately, this process strips the oils of their beneficial properties and as a result, trans fats have the same poor health effects that saturated fats have and should be completely avoided if possible.

Good fats are important for supporting heart health and also aid in hormone production in the body. They should not be avoided, but need to be eaten in moderation. Each gram of fat contains 9 calories (unlike protein and carbohydrates, which both contain 4 calories per gram) and thus it is much easier to overshoot your caloric intake goals for the day if you’re not monitoring the amount of fat you consume.

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