Everything You Need to Know About The Functions of Fats in Foods
Think for a moment of your favorite foods...
What is it about them you enjoy most? The flavor of a rich, succulent steak or delicious hamburger? The creaminess of ice cream or chocolate as it melts on your tongue? The pleasing contrast of a silky smooth salad dressing with the crunch of fresh vegetables? That satisfied feeling that follows a snack of cheese or peanut butter on crispy crackers or celery?
These foods, all of which rank high on many people's lists of favorites, share a common trait. They contain fats. Fats provide much of the great taste and texture for which we prize these and other foods.
Indeed, the fats in foods play a vital role in their ultimate acceptability. Neither the amount nor type of fats can be changed indiscriminately without changing the very features that make a food appealing.
Without fats, foods - and eating - just wouldn't be the same. But with attention focused on reducing fats in our diets, we may forget the important role fats play in foods. This brochure explains why fats are necessary in many foods as well as their place in a healthful diet.
What are fats?
Fatty acids may be thought of as the "building blocks" of fats. All fats are a mixture of saturated, monounsaturated and polyunsaturated fatty acids. They differ in the amount of hydrogen they contain. Saturated fatty acids contain the most hydrogen (they are "saturated" with hydrogen). Polyunsaturated fatty acids contain the least amount of hydrogen.
What foods contain fats?
Many foods naturally contain fats. Meats, dairy products, poultry, fish, nuts and vegetable oils supply most of the fats Americans eat. Whole grains and vegetables contain only small amounts of fats when prepared without added fats. Fruits (except avocados, coconut and olives) contain virtually no fats.
Many prepared foods also contain fats. Whether a cake is made from "scratch" at home, from a mix or purchased at the bakery, fats are frequently a key ingredient. Further, there are grocery staples that are fats, such as butter, margarine products, shortening and oil.
Why do we need different products like butter, shortening, margarine products and oil?
Fats serve a variety of functions in foods. Their unique mouthfeel supplies the rich, smooth, creamy sensation that distinguishes many foods. Fats also absorb and blend ingredient flavors and aromas to produce the distinct taste of individual foods.
In baked goods such as cakes, fats help produce a high, fine texture. When "creaming" fats and sugar -- the first step in mixing many cake batters -- fats trap tiny air bubbles that help the batter to rise. Fats also help keep doughs and batters from separating and falling. And fats coat the proteins in flour to make a tender or flaky product.
While butter, shortening, margarine products and oil contain fat, each have different properties that affect how they work. Thus, they produce different results that can be key to the acceptance of many foods.
As every cook knows, shortening works best for some types of baking. It contains no water that would otherwise mix with flour and form gluten that toughens a product. As a result, shortening produces tender, flaky pie crusts and biscuits. Butter and margarine products contain water and hence produce a different, but still acceptable, texture. Oil yields the best results in many box cake mixes.
Restaurants also depend on shortening to produce crispy French fries. French fries cooked in oil have a softer texture.
The flavor of fat-containing products affects their use as well. While many people prefer olive oil for sautéing, its distinctive taste may not be right for other uses, such as in baked products.
Many people use margarine products because they contain less saturated fat than butter. And margarine products made from vegetable oil are cholesterol-free and a major source of essential fatty acids. The chart on the back of this brochure describes how different fat-containing products work in different uses.
What is the difference between solid fats like butter and shortening and liquid fats such as vegetable oils?
Many of the differences relate to the type of fatty acids they contain. All fats contain both saturated and unsaturated fats. Fats with a higher level of saturated fats are firmer at room temperature and need more heat to melt. They perform better in certain uses, such as when creaming a cake batter. Fats with a higher level of unsaturated fats tend to be liquid at room temperature. They may be more useful in other recipes, such as when making salad dressings.
Although they may be solid, most shortening and margarine products are made from liquid vegetable oils that have been partially hydrogenated. These products are hydrogenated only as much as needed to produce the desired texture and taste. Hydrogenation increases the firmness and melting point of oils. Partially hydrogenated products still contain more unsaturated than saturated fats.
Trans fats are produced when unsaturated fats and oils are partially hydrogenated. They also occur naturally in small amounts in meats and dairy products. Trans fats make up a small percentage, between two and three percent, of the total fat intake in the average American diet.
What role do dietary fats play in the diet?
The fats that we get from food are vital to good health. They provide energy -- 9 calories per gram -- and essential fatty acids for healthy skin and important hormone-like substances. Fats also carry and help the body absorb the fat-soluble vitamins A, D, E and K. What's more, dietary fats help us feel satisfied following meals.
A balanced diet contains moderate amounts of fats. National dietary guidelines advise us to reduce total fat to an average of 30 percent of calories. Less than one-third of total fat calories should come from saturated fat. For example, if you eat 2,000 calories a day, your fat intake should be, on average, 65 grams of total fat and approximately 20 grams of saturated fat. The average American now eats about 34 percent of calories from fat; about 12 percent of calories come from saturated fat.
To reduce fats, health experts recommend an eating pattern rich in a variety of grains, fruits and vegetables. Lean meats, poultry and fish, lowfat dairy products and fats and oils found in margarine products, butter, oil and salad dressings should be used in moderation. As one step to help reduce saturated fat intake, the American Heart Association recommends soft margarine and spreads instead of butter and other solid fats.
How do dietary fats affect blood cholesterol?
The type and amount of dietary fats may affect levels of blood cholesterol. High blood cholesterol levels are one risk factor for coronary heart disease. Studies show some saturated fats raise blood cholesterol levels and unsaturated fats lower levels. Saturated fats are typically found in higher amounts in meats, egg yolks, whole milk and milk products. Unsaturated fats are found in higher amounts in nuts and liquid vegetable oils.
Research suggests that fats containing trans fats, such as shortening and margarines, have a similar affect on levels of total and LDL-cholesterol (the "bad" cholesterol) as saturated animal or vegetable fats such as butter or lard. More research is needed to determine the overall impact of trans fats on heart disease risk.
Most nutritionists agree, however, that the most important priority for Americans is to reduce saturated and total fat in the diet, especially if you are at high risk of heart disease.
How is cholesterol used by the body?
Cholesterol is a part of all body cells and plays key roles in the formation of brain and nerve tissues and some hormones. But you don't need to get cholesterol from foods. The body makes its own supply.
Whether it comes from food or is made by the body, cholesterol circulates in the blood and is known as "blood" or "serum" cholesterol. Several factors, including heredity, affect your blood cholesterol level.
What is the difference between dietary cholesterol and fats in foods?
Foods with fats do not necessarily contain dietary cholesterol. Dietary cholesterol, a fat-like substance, is found only in animal products such as meats, dairy products, butter and egg yolks. It is not found in vegetable oils, margarine, egg whites or plant foods like grains, fruits and vegetables.
What is the bottom line concerning fats in foods?
Fats play a vital role in the taste, texture and appearance of foods. Consumers select fat-containing products according to how they intend to use them at home. Likewise, manufacturers choose different products to balance flavor, texture and nutritional aspects. A manufacturer might make a cookie, for example, using shortening because it produces the texture, flavor and freshness qualities consumers want. Olive oil might be added to a salad dressing to give it a certain flavor.
The principles of balance, variety and moderation form the basis for a healthful diet. Along with appropriate amounts of grains, vegetables, fruits, dairy products and meat/meat alternatives, consumers can enjoy moderate amounts of fat-containing products to add appeal to foods. The Nutrition Facts panel on the food label can help you determine the amount of fat and saturated fat in foods. By balancing high-fat items with low-fat choices, Americans can reduce dietary fat while continuing to take pleasure in eating.
|Butter & Margarine (80% fat)|
|Adds flavor; produces tender, crisp, chewy and brown cookies; tender pie crusts; cake frostings||Pan sautéing; burns easily||Suitable for spreading directly on foods|
|Margarine Spreads (20% - 60% fat)|
|Cookies have "cake-like" texture; not suitable for pie crusts||May not be suitable||Suitable for spreading directly on foods|
|Nonfat/Very Low fat Spreads (0% - 10% fat)|
|Not suitable||Not suitable||Suitable for spreading directly on foods|
|For special recipes such as carrot cake, box cake mixes and quick breads||Pan sautéing; frying and deep-fat frying||Mix with vinegar or herbs/spices|
|Produces tender, light, moist texture; best for flaky pie crust; thick cake frostings||Pan sautéing; frying and deep-fat frying||May not be suitable|
|Pan coating||Can be used to sauté in non-stick pans, if watched carefully||Not suitable|
|Special recipes; some box cake mixes||May not be suitable||Suitable for use directly on/in foods and in marinades|
If You Want to Know More
A registered dietitian (R.D.) is an authority on food, nutrition and health and can provide valuable information and advice. To locate a registered dietitian in your area, or listen to recorded messages in English or Spanish, call the Consumer Nutrition Hot Line of The American Dietetic Association's National Center for Nutrition and Dietetics at 800-366-1655, Monday through Friday from 9 a.m. to 4 p.m. For customized answers to your food and nutrition questions, call 900-CALL-AN-RD (900-225-5267). Charges are applicable.
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