Facts about Fat
Why do we need fat?
Fats, just like carbohydrates and proteins, provide calories or energy. Fat is required to transport vitamins A, D, E and K, produce hormones, store energy, maintain healthy skin, and protect organs. Fat also gives flavor and texture to foods. Although every person needs fat in their diet, the type and amount of fat eaten can influence one’s health.
How much fat do we need?
A healthy diet contains approximately 20-35% of calories from fat. This translates into about 40-70 grams of fat per day for college-aged women on an 1800 kcal/day diet and 45-77 grams of fat per day for college-aged men on a 2000 kcal/day diet. Although too little fat in the diet can cause serious problems, most individuals in the United States need to be concerned with eating too much fat rather than too little.
Why is a high fat diet dangerous?
Too much fat in the diet can increase the risk of obesity, heart disease, cancer, and diabetes. A high fat diet can be dangerous because of the amount or the types of fat eaten. Too much of any macronutrient, be it carbohydrate, protein, or fat, can lead to weight gain. However, since fat provides more than double the calories that carbohydrate or protein provide per gram, too much dietary fat often leads to excess weight gain. Eating high amounts of certain types of fat can also be dangerous because of their impact on heart health.
What are the different types of fat?
There are three main types of fat found in foods:
- Saturated fat
- Unsaturated fat
- Trans fat
What is saturated fat?
Saturated fats are often solid at room temperature and can come from animal or plant sources. Saturated fats are the main dietary culprit in raising blood cholesterol and increasing the risk of heart disease. Some sources of saturated fat in the typical American diet are foods like:
- Hot dogs/sausages
- Whole milk
- Fatty cuts of meats
- Tropical oils like palm or coconut oil
What is unsaturated fat?
Unsaturated fats are usually liquid at room temperature and are often found in liquid vegetable oils. There are two main types of unsaturated fats; polyunsaturated and monounsaturated fats. Both types of unsaturated fats may help lower blood cholesterol levels when used in place of saturated fats. However, it is important to not eat too much of any type of fat because all types of fat are high in calories, which can lead to weight gain.
Polyunsaturated fats are liquid at room temperature and in the refrigerator. Common sources of polyunsaturated fats are:
- Safflower oil
- Soybeans and soybean oils
- Sesame and sunflower seeds
- Most nuts and seeds, and their oils
- Corn oil
Monounsaturated fats are liquid at room temperature, but start to solidify at refrigerator temperatures. Common sources of monounsaturated fats are:
- Canola oil
- Peanut oil
- Olive oil
What are trans fats (or hydrogenated fatty acids)?
During food processing, some fats may undergo a chemical process known as “hydrogenation”. This process changes liquid oil naturally high in unsaturated fats, to a more solid and more saturated form. Hydrogenation may be used to increase the shelf life of a product, or it may be used to turn liquid oil into a more solid spreadable form. Margarine, for example, is made by hydrogenating liquid vegetable oil to make a more solid product. Some products that are likely to contain trans fat include:
- French fries
- Baked goods
- Fried foods
Recent studies suggest that trans fats may raise total blood cholesterol levels and LDL (“bad”) cholesterol and lower HDL (“good”) cholesterol when used instead of unsaturated fats. This could result in a greater risk for developing cardiovascular disease. The American Heart Association recommends that we use “trans fat free” spreads instead of butter or margarine spreads that contain trans fats.
How can I lower my total fat intake?
Choose lean meats and leaner cuts of meat. Try skinless chicken, fish, and 90-95 percent lean ground beef. Choose cuts of red meat such as top loin, sirloin, round or flank steak. Trim fat from meat and drain fat once it is cooked.
Use 1/2 less fat in every recipe without changing flavor or texture.
Limit the sauces, dressings, and gravies on foods.
Make substitutions in recipes. Try 2 egg whites instead of one whole egg (all the fat in eggs is found in the yolk), or replace 1 cup of sour cream with 1 cup of plain nonfat yogurt. Use ground turkey, ground chicken, tofu or textured soy protein instead of ground beef.
Reduce high-fat dairy products. Choose skim or 1 percent milk, lowfat yogurt, and reduced fat cheese. Try lowfat frozen yogurt or sherbet instead of ice cream.
Use herbs and spices to enhance flavor, rather than added fat or salt.
How can I substitute Unsaturated Fats for Saturated Fats?
- Use liquid fat (oils) versus butter or shortening in baking.
- Use olive, canola, or corn oil in cooking or baking.
- Use cooking spray for baking rather than butter or oil.
References:American Heart Association: www.americanheart.org
A.D.A.M. Medical Encyclopedia. Atlanta (GA): ADAM, Inc. “Fat” updated 02 Aug 2009. cited 10 May 2010. Available from: http://www.nlm.nih.gov/medlineplus/ency/article/002468.htm