Fat's role in a healthful diet

Laura Walsh-Sponaugle

Fat and oils play a slick role in a healthful diet and bodily functions

Most chefs know the value of oils–fat–in cooking. It acts not only as a cooking medium but it imparts flavor, mouth-feel and helps to crisp foods for both eye and palate appeal. And fat is an essential part of a healthful diet. Here are some fat facts every operator should know.

Fat’s Role: Good and Bad

Fat is a concentrated energy source and it’s vital to one’s health. It helps the body absorb fat-soluble vitamins (Vitamins A, D, E and K), maintain healthy skin synthesize hormones. It also cushions body organs from injury and provides energy stores. There are even some fatty acids (linoleic and linolenic acid) that your body can’t make that you have to get from your diet.

So fats serve an essential purpose in the diet and are beneficial to one’s health–as long as you don’t get too much in your diet. A total fat intake of no more than 30% of calories or less from fat is recommended. A diet too high in fat is associated with increased blood cholesterol levels, and high blood cholesterol is a risk factor for heart disease. A high fat diet may also increase chances for developing some types of cancer and obesity.

Types of Fat

Fats are made up of a variety of fatty acids: monounsaturated, polyunsaturated, saturated, Omega-3 and trans fatty acids.

Monounsaturated fatty acids are generally liquid at room temperature. Canola, nut and olive oils are high in monounsaturated fatty acids. These fatty acids help improve HDL (good cholesterol) levels and make these oils desirable for cooking. (However, many of these oils do have a flavor so they aren’t always the best choice in baked goods.)

Polyunsaturated fatty acids are generally liquid or soft at room temperature. Safflower, corn, sunflower and soybean oils are high in polyunsaturated fatty acids. These fatty acids may help lower LDL cholesterol (bad cholesterol) while not altering or lowering HDL (good cholesterol) levels. The Omega-3 fat in seafood is mainly polyunsaturated, too. And they are mostly found in fattier fish like tuna and as well as in flaxseed. These fatty acids may help prevent heart disease, relieve some symptoms of rheumatoid arthritis and possibly ease depression.

Saturated fatty acids are generally solid at room temperature. They come mainly from animal products like meat, poultry and milk but also from palm and coconut oils. When these fatty acids are eaten in amounts larger than recommended (less than 10% of calories), they stimulate the liver to produce more cholesterol. This results in higher blood cholesterol levels and an increased risk for heart disease.

Trans fatty acids are formed during hydrogenation, the process that solidifies liquid fats. Research suggests that these fatty acids have the same effect on blood cholesterol as saturated fat and should be limited in the diet.

Cooking with Fat

Fat has many purposes in cooking and can be used in a variety of ways. It adds moisture to baked goods by trapping air making them light and tender. It holds foods together to form an emulsion and makes food like sauces creamy. It also carries flavor and nutrients and helps to brown and crisp foods. And it is also used to help conduct heat when sautéing or frying and prevents foods from sticking.

The type of fat (butter, shortening, margarine,oil) to use depends on what you are making–each fats different properties affect how they work. Shortening works well for baking since it has no water that would mix with flour to form gluten, which makes a tougher product. It produces a tender, flaky product and works well for making biscuits or pie crusts.

Butter and margarine contain water, so they work well in most desserts, sauces and for general cooking purposes. Oils work well to make roux, salad dressings and sauces and yield the best results in many box cake and brownie mixes.

Try to use monounsaturated fats whenever possible because of their favorable effects on cholesterol levels. If you can’t, polyunsaturated fats are a good substitute. But remember for health’s sake, saturated and hydrogenated fat should be limited in the diet.

Laura Walsh-Sponaugle, R.D, L.D., is an independent food and nutrition consultant based in Elmhurst, Illinois.