Fat and Fatty Acids

Fat is a major source of fuel energy for the body. Fat is a nutrient that is an important source of calories. One gram of fat supplies 9 calories - more than twice the amount we get from carbohydrates or protein. Fat also is needed to carry and store essential fat-soluble vitamins, like vitamins A and D. There are two basic types of fat. They are grouped by their chemical structure. Each type of fat is used differently in our bodies and has a different effect on our health.

When we eat a lot of high fat foods, we get a lot of calories. With too many calories, we may gain weight. Eating too much fat may also increase the risk of getting diseases like cancer, heart disease, high blood pressure or stroke. Health experts recommend that we should get no more than 30% of our calories from fat to reduce our risk of getting these diseases.

Fat is found in many foods. Some of the fat that we eat comes from the fat we add in cooking or spread on breads, vegetables or other foods. A lot of fat is hidden in foods that we eat as snacks, pastries or prepared meals.

We can reduce the amount of fat we eat by cutting down on the fat that we add in cooking or spread on foods. We can eat skim milk and low fat cheeses instead of whole milk and cheese. We can also use less fat, oil, butter, and margarine. Another way to cut down on fat is to drain and trim meats and take the skin off poultry. We can also read labels and compare the amount of fat in foods to make lower fat choices.

Why do we need fats?

Although fats have received a bad reputation for causing weight gain but still some fat is essential for survival. According to the Dietary Reference Intakes published by the USDA 20% - 35% of calories should come from fat. We need this amount of fat for:
Body to use vitamins: Vitamins A, D, E, and K are fat-soluble vitamins, meaning that the fat in foods helps the intestines absorb these vitamins into the body.

Brains development:Fat provides the structural components not only of cell membranes in the brain, but also of myelin, the fatty insulating sheath that surrounds each nerve fiber, enabling it to carry messages faster.

Energy: Gram for gram fats is the most efficient source of food energy. Each gram of fat provides nine calories of energy for the body, compared with four calories per gram of carbohydrates and proteins.

Healthier skin: One of the more obvious signs of fatty acid deficiency is dry, flaky skin. In addition to giving skin its rounded appeal, the layer of fat just beneath the skin acts as the body's own insulation to help regulate body temperature.

Healthy cells: Fats are a vital part of the membrane that surrounds each cell of the body. Without a healthy cell membrane, the rest of the cell couldn't function.

Making hormones: Fats are structural components of some of the most important substances in the body, including prostaglandins, hormone-like substances that regulate many of the body's functions. Fats regulate the production of sex hormones, which explains why some teenage girls who are too lean experience delayed pubertal development and amenorrhea.

Pleasure: Besides being a nutritious energy source, fat adds to the appealing taste, texture and appearance of food. Fats carry flavor.

Protective cushion for our organs: Many of the vital organs, especially the kidneys, heart, and intestines are cushioned by fat that helps protect them from injury and hold them in place.

Types of Fat

Dietary fats are classified by their structure. Different types of fats react differently inside the body. Saturated fats (found mostly in animal products) increase blood cholesterol, which is a risk factor in coronary heart disease. Mono-unsaturated and polyunsaturated fats tend to lower blood cholesterol.

Dietary fats and blood cholesterol

There are two types of blood cholesterol: low density lipoprotein (LDL) cholesterol and high density lipoprotein (HDL) cholesterol. LDL is considered the ‘bad’ cholesterol because it contributes to the narrowing and silting up of the arteries, which can lead to heart disease and stroke. HDL cholesterol is considered to be the ‘good’ cholesterol because it actually carries cholesterol from the blood back to the liver, reducing the risk of cardiovascular disease.

Groups of fats

Each group of fats behaves differently inside the body. Dietary fat can be classified into three groups:
• Saturated
• Un-Saturated Fats
• Trans Fats or Hydrogenated Fats

Saturated Fats

Saturated fats are the animal-derived 'hard' fats such as butter, lard and fat in meat (and used in many processed foods). But they are also found in some plant-based sources such as coconut, palm and palm kernel oils. These fats are solid at room temperature. Saturated fats directly raise total and LDL (bad) cholesterol levels. These are the fats to reduce in the diet.

Unsaturated fats

Monounsaturated fats and polyunsaturated fats are two types of unsaturated fatty acids. They are derived from vegetables and plants.

Monounsaturated fats are liquid at room temperature but begin to solidify at cold temperatures. This type of fat is preferable to other types of fat and can be found in olives, olive oil, nuts, peanut oil, canola oil and avocados. Some studies have shown that these kinds of fats can actually lower LDL (bad) cholesterol and maintain HDL (good) cholesterol.

Polyunsaturated fats are also liquid at room temperature. These are found in safflower, sesame, corn, cottonseed and soybean oils. This type of fat has also been shown to reduce levels of LDL cholesterol, but too much can also lower your HDL cholesterol.

Trans Fats or Hydrogenated Fats

Trans fats are produced when liquid oil is made into a solid fat. This process is called hydrogenation. Trans fats act like saturated fats and can raise your cholesterol level. Trans fats are listed on the label, making it easier to identify these foods. Unless there is at least 0.5 grams or more of Trans fat in a food, the label can claim 0 grams. If you want to avoid as much Trans fat as possible, you must read the ingredient list on food labels. Look for words like hydrogenated oil or partially hydrogenated oil. Select foods that either does not contain hydrogenated oil or where liquid oil is listed first in the ingredient list.

Sources of Trans fat include:

Processed foods like snacks (crackers and chips) and baked goods (muffins, cookies and cakes) with hydrogenated oil or partially hydrogenated oil
Stick margarines
Some fast food items such as French fries