Fats
American Heart Association recommendation: Limit foods high in saturated fat, trans fat, and/or cholesterol, such as full-fat milk products, fatty meats, tropical oils, partially hydrogenated vegetable oils, and egg yolks. Instead choose foods low in saturated fat, trans fat, and cholesterol.

Choose fats with 2 grams or less of saturated fat per serving, such as liquid and tub margarines, canola oil, and olive oil.

Believe it or not, cholesterol and fat are both necessary for good health. Fat is necessary to carry fat-soluble vitamins through the bloodstream. Fat also supplies energy, cushions your vital organs, offers insulation against cold, and satisfies your hunger.

Cholesterol
Cholesterol is found in only foods of animal origin, such as eggs, meat, poultry, seafood, and dairy foods. It is part of every body cell and of some hormones, including estrogen. As part of a chemical called bile, cholesterol helps the body digest fat. Cholesterol can even be converted to vitamin D in the presence of sunlight. The caveat here, of course, is that eating too much of some kinds of fat or cholesterol can lead to atherosclerosis (fatty deposits in the arteries) and increased risk for cardiovascular disease.

Fats
The major kinds of fats in the foods we eat are:

• saturated fats
  This is the artery-clogging kind. Foods high in saturated fat include animal products, such as meat, poultry, butter and whole milk, as well as tropical oils (coconut, palm, and palm kernel). Eating too much saturated fat increases risk for cardiovascular disease.
  
• polyunsaturated fats
  Polyunsaturated fats can help decrease high blood cholesterol levels. These are usually liquid or soft at room temperature, and include safflower, sunflower, corn, sesame, and soybean oils, as well as certain types of fish.
  
• monounsaturated fats
  Monounsaturated fats can also help decrease high blood cholesterol levels if they make up a significant proportion of a lower-fat diet. They are usually liquid at room temperature and include olive oil, canola oil, peanut oil, avocados, and nuts.
  
• trans fats
• unsaturated fats

Be moderate in eating all types of fat, because fats contain more than twice the calories of either protein or carbohydrate. One gram of fat contains nine calories, while one gram of protein or carbohydrate provides four calories.

Foods often have more than one type of fat. As a general rule, those that have mostly saturated fat are thicker (butter, lard, cream), while those that are mostly unsaturated are thinner (oils).

Trying to eliminate all fats from your diet is not an alternative, because some fat and fatty acids in the diet are necessary to maintain proper health.

Researchers advise consumers to reduce their intake of both saturated and trans fats. They recommend that vegetable oils be used in their natural liquid state whenever possible, and say that less hydrogenated semi-liquid or soft margarines are a better choice than either stick margarine or butter.

Saturated Fat
Foods rich in saturated fat include:

• whole milk
• cream
• ice cream
• whole-milk cheeses
• butter
• lard
• meats
• palm and palm kernel oil
• coconut oil
• cocoa butter

Many snack foods and fried foods are also rich in saturated fat. Check the Nutrition Facts label to find the saturated fat content of a specific food.

For many of these foods that are naturally rich in saturated fat, there are low-fat versions. Some are more palatable than others, so try a variety of them to find ones you like. Use these lower-fat versions, or use the original versions very infrequently. Also, try to choose naturally lower-fat foods. For example, have fruit and gingersnaps for dessert instead of ice cream, and eat fish and vegetarian-based dinners several times a week in place of meat.

Trans Fat
Through the process of hydrogenation, trans fats are made. This process takes a vegetable oil, which is naturally high in unsaturated fatty acids, and adds hydrogen molecules to it to make it more saturated and more solid. Depending on how many hydrogens are added, the result of this process can be a hydrogenated oil or a solid margarine. These products do not contain cholesterol, as butter does; any food that comes from a plant does not contain cholesterol.

Hydrogenated oils are used to make many processed snack foods. Foods rich in trans fat include:

• margarine
• cookies
• crackers
• cakes
• french fries
• fried onion rings
• donuts

Unlike saturated fats, trans fats are not listed on the Nutrition Facts food label. Look at the ingredient list. If "hydrogenated oil" or "partially hydrogenated oil" is listed, that means the food contains trans fat.

According to the American Heart Association, hydrogenated fats in margarine and other fats are acceptable if the product contains liquid vegetable oil as the first ingredient and no more than 2 grams of saturated fat per tablespoon.

Butter vs. Margarine
Although butter and regular margarine have the same amount of fat and calories, margarine has less saturated fat. So, margarine made from vegetable oil was once thought to be a better choice than butter or lard in the context of a healthy eating plan, which calls for a reduction in saturated fat to less than 10 percent of total calories. (Current recommendations endorsed by both the U.S. government and the American Heart Association recommend that total fat-including saturated fat-not exceed 30 percent of daily total calories).

But margarine undergoes a process called "hydrogenation" to convert it from its liquid vegetable state to a more solid whipped or stick state. This process creates a compound called trans fat, which studies have shown may actually raise levels of low-density lipoproteins (LDL, or bad cholesterol) and may lower levels of the more beneficial high-density lipoproteins (HDL, or good cholesterol).

Since both the saturated fat in butter and the trans fat in margarine can raise blood cholesterol levels, which is the best one to eat? There is no definitive answer to this question. When choosing your spread, consider the following:

• The softer the better:

Whipped butter has less saturated fat than stick butter.
Liquid and soft tub margarine contain little saturated fat or trans fat.

• Whichever you choose, limit the amount you use.
• When cooking and baking, substitute an unsaturated oil for butter or margarine.
• Some margarine products, like Promise Ultra and Smart Balance, have been developed that do not contain trans fats. Be sure to check the label of any product you're considering.

Unsaturated Fat
You can feel good about eating this type of fat! But unsaturated fats still deliver as many calories as the saturated varieties, so don't go overboard. Foods rich in polyunsaturated fats include:

• nuts
• seeds
• certain oils:

safflower
sesame
soy
corn
sunflower-seed

Foods rich in monounsaturated fats include:

• avocados
• certain oils:

  olive
  canola
  peanut

It's easy to work these foods into your diet:

• Combine nuts, seeds, dry cereal, and dried fruit for a snack mix.
• Use mashed avocado as a sandwich or bagel spread.
• In sesame oil, sauté vegetables, tofu, and peanuts.
• Bake pecans or walnuts into breads, pancakes, and muffins.
• Use an oil sprayer for your cooking oils; spray meats and vegetables and sprinkle with herbs before cooking.
• Coat salmon or tuna steaks in sesame oil and sesame seeds before broiling.

Essential Fatty Acids
The building blocks of dietary fats are fatty acids. Once fats are consumed, they are broken down into fatty acids, which are used for energy, growth, development, and the formation of important cellular components.

Fortunately, the body can synthesize most of the fatty acids that it needs. However, certain fatty acids cannot be synthesized by the body, and these are called "essential fatty acids" and must be consumed in the diet. The two main types of essential fatty acids are omega-6 and omega-3.

While a balance of omega-6 and omega-3 is desirable, most Americans consume more omega-6 than omega-3. Omega-3s are important for brain and vision development in infants and may affect learning, memory, and stress levels throughout life. The best sources of omega-3 fatty acids are fatty fish (salmon, tuna, mackerel, herring, sardines) and flaxseed oil.

Flaxseed oil has been shown in studies to increase the ratio of omega-3 to omega-6 fatty acids in the body and to offer some protection against cardiovascular disease. Flaxseed oil contains alpha-linolenic acid, an omega-3 fatty acid, and is the precursor to fatty acids found in fish oil.

Flaxseed oil is sold as a dietary supplement and flaxseeds can be added to baked goods. Some people may prefer to get their omega-3 fatty acids from flaxseed rather than from fish oil, because flaxseed oil has a more pleasant taste and smell. Also, omega-3 fatty acids from flaxseed oil can be stored in the body until they are needed, while the body has no ability to store omega-3 found in fish oil.