Fats in Your Diet

When most people hear the word "fat," they think of the gristle that they see on a piece of meat or a person's excess weight. When people talk about fats in food, they are talking about dietary fats, or triglycerides. Triglycerides are fatty acids that are bound together with glycerol, a chemical compound that acts as a glue to hold the fat together.

Fats are necessary in your diet because they:

Types of Fats

There are four types of dietary fats. They each play different roles in your diet. You will want to keep some fats in your diet since they are necessary for good health while reducing or eliminating others. Here we call them "good fats" (they don't cause health problems) and "bad fats" (they do cause health problems).

Good Fats
Monounsaturated fat
The name "monounsaturated" is used to describe the way the fatty acid is structured. The molecules, or small cellular pieces, of carbon bond together with hydrogen to form a single bond. Monounsaturated fats are liquid at room temperature.
Monounsaturated fats are "good" fats. They are fats that lower low-density lipoprotein (LDL), or bad cholesterol, in your blood. They may also raise the levels of high-density lipoprotein (HDL), or good cholesterol, in the blood.
Foods that contain monounsaturated fats are: olive oil, peanut oil, canola oil, avocados, and nuts (such as peanuts, walnuts, almonds, and pistachios).


Polyunsaturated fat
As with monounsaturated fat, the name for polyunsaturated fats comes from the way the molecules make the fat. In this case, the molecules of carbon have two or more bonds that hold them together. Polyunsaturated fats are liquid at room temperature.
Polyunsaturated fats are also "good" fats. As with monounsaturated fats, they lower LDL while possibly raising HDL levels in the blood. Our bodies do not naturally make polyunsaturated fats, so we have to get them through our diets. Polyunsaturated fats are split into two groups, n-6 and n-3. These numbers refer to how far the double bonds linking the molecules are from each other. n-3 fats are more commonly referred to as Omega-3 fatty acids.
Foods that contain polyunsaturated fats are: foods made from plant oils like corn and soybean oils, seeds, whole grains, and fatty fish (salmon and tuna).
Bad Fats
Saturated fat
Fats are called saturated when the carbon molecules hold as many hydrogen molecules as they can. Saturated fats are solid at room temperature. Think of the last time you cooked a hamburger. When the burgers are cooking, the oils in the pan are liquid. If you turn off the heat, and let the pan sit for awhile, the oils in the pan turn solid. The oil turns solid because of the saturated fats that were released from the meat during the cooking process.
Saturated fats are considered "bad" fats because they are more likely to raise LDL in the blood while not affecting HDL. Since higher levels of LDL in the blood can lead to health issues, you should minimize the amount of saturated fat in your diet.
Saturated fats can be found in meats, dairy, eggs, chocolate, and nuts.


Trans fat
Trans fat are man-made fats. A century ago, food chemists found a process that would allow them to make polyunsaturated fats solid at room temperature. This discovery was praised at the time because it made shipment of oils easier because the liquids could be turned into a solid form.
Not only does trans fat raise the level of LDL in the blood, but a study from Holland has shown that trans fat lower HDL, or the good cholesterol, in the blood. (from Eat, Drink, and Be Healthy p. 73) Trans fat are a "bad" fat.
Trans fat can most commonly be found in baked goods and foods that have been deep fried.

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How much Fat Should I Eat?

At this point, you must be wondering how much fat you should be eating in your diet. From the information on this page, you should know that you should concentrate on consuming monounsaturated and polyunsaturated fats while limiting the amount of saturated and trans fat.

The dietary guidelines listed below are recommended by the American Heart Association. Remember, before starting any diet, you should check with your physician to make sure that the diet is a good one for you. The AHA recommendations are:

If you are not sure how many calories you should eat, you can go to the My Fats Translator page. The site is prepared by the American Heart Association. Put in your age, sex, ideal weight (maybe not what you weigh now but how much you would like to weigh), height, and how much you exercise. You will then find out how many calories and fat you should have in your diet.

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Atkins Diet Controversy

In 1972, Dr. Robert Atkins wrote Dr. Atkins' Diet Revolution. The idea behind the book was that carbohydrates were bad for you. If a person went on a diet that limited how many carbohydrates (foods with sugar, flour, and high-fructose corn syrups) he or she ate every day, he or she would lose weight. Dr. Atkins felt that unsaturated fat was unfairly blamed for heart problems, and that trans fat was more of the culprit in heart disease. People would lose weight and maintain good health on the Atkins Diet because they would eat fewer processed foods which contained trans fat and high-fructose corn syrup. A person on the Atkins Diet will start to burn stored body fat instead of glucose, which are sugars in the body. The diet developed a huge following because it did help people to lose weight. What should be noted is that the Atkins diet does make a distinction about the types of fat. Although Dr. Atkins didn't think that saturated fat was as bad for your health as others stated, he agreed that trans fat should be avoided. As with any diet you may choose to follow, please talk to your physician first.

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Page updated on August 27, 2009

©Fats Organization