Essential substances, including fats, must be ingested in optimum quantities to build optimum health. Surveys show that the majority of the members of affluent populations are obtaining too little of many essential substances, leading to deteriorating health which in turn leads to degeneration due to malnutrition and ultimately kills two-thirds of the world's population.

In fact, more than 70% of people die from just three conditions that involve fatty degeneration: cardiovascular disease (50%), cancer (25%), and diabetes (3%).
The fact is that some fats are absolutely required for health while others are detrimental. If the right kinds of fats are ingested in the right amounts and balances, they build our health and keep us healthy. The wrong kinds of fats, the wrong amounts and balances can cause degenerative diseases.

Fatty acids are part of the basic structure of dietary fats. Almost all dietary fats contain a mixture of saturated, monounsaturated and polyunsaturated fatty acids. The type of fatty acid that predominates determines whether it is solid or liquid as well as its stability. They are key building blocks of all fats and oils (lipids) both in our foods and in our body. Fatty acids are also the main components in neutral fats (triglycerides) carried in our blood, and stored fat (adipose) which serves as an important source of energy.

Saturated Fats
Saturated fats are found primarily in animal products such as beef, veal, pork, lamb, and ham as well as whole milk, cream, coconut oil, and vegetable shortening.

Saturated fats are used by the body to make cholesterol. A high dietary intake can raise LDL (‘bad’ cholesterol) levels in the blood, increasing your risk of heart disease.

It is recommended to limit your intake of saturated fats to less than 10% of your total daily calories.

Polyunsaturated Fats
Found mostly in corn, soybean, safflower, and sunflower oils and certain fish oils, these fats may actually lower your total blood cholesterol levels. But they may also lower your good cholesterol (HDLs) and are still high in calories. They should not exceed 10% of your total daily caloric intake.

Monounsaturated Fats These fats are found in olive, peanut, and canola oils. It is thought that monounsaturated fats may reduce LDLs (bad) without affecting HDLs (good). It is recommended that these fats make up no more than 10-15% of your total caloric intake.

Trans-fatty acids
Trans-fatty acids occur when polyunsaturated fats are hydrogenated to make margarine and shortening. While the jury is still out, it is thought that trans-fatty acids behave much like saturated fats, raising LDL cholesterol.

Essential Fatty acids (EFA)
Essential fatty acids are sources of Omega-6 and Omega-3 fatty acids (technically categorized as polyunsaturated fatty acids). They include linoleic and linolenic acids. The body must have these essential fatty acids, yet cannot synthesize them itself. One of the main functions of essential fatty acids is the production of prostaglandins which are hormone-like substances that regulate many body functions. They basically control every cell of the body on a second-by-second basis. They are required for energy production and increase oxidation and metabolic rate. Some of the many benefits of EFA's for the body are reducing blood pressure, preventing inflammation, stimulating immunity, reducing joint tenderness, and positively influencing HDL/LDL cholesterol levels.

Cholesterol
We are conditioned to think of cholesterol as the enemy, our bodies do need cholesterol. In fact, much of our cholesterol is made in-house, by the liver. People don't need to consume dietary cholesterol because the body can make enough cholesterol for its needs. But the typical diet contains substantial amounts of cholesterol, found in foods such as egg yolks, liver, meat, some shellfish, and whole-milk dairy products. Only foods of animal origin contain cholesterol.

Cholesterol is transported in the bloodstream in large molecules of fat and protein called lipoproteins. Cholesterol carried in low-density lipoproteins is called LDL-cholesterol; most cholesterol is of this type. Cholesterol carried in high-density lipoproteins is called HDL-cholesterol. LDL-cholesterol and HDL-cholesterol act differently in the body. A high level of LDL-cholesterol in the blood increases the risk of fatty deposits forming in the arteries, which in turn increases the risk of a heart attack. Thus, LDL-cholesterol has been dubbed "bad" cholesterol. On the other hand, an elevated level of HDL-cholesterol seems to have a protective effect against heart disease. For this reason, HDL-cholesterol is often called "good" cholesterol.

Body Fat
Body fat (fat present in the cells of adipose tissue) is probably the fat that most people are familiar with. Body fat is vital to daily body functions. It cushions the joints and protects the organs, helps regulates body temperature, stores vitamins and helps the body sustain itself when food is scarce. However, serious health risks have been associated with both too much and too little body fat.
The following table describes body fat ranges and their associated categories:

Source: http://preventdisease.com/fitness/nutrition/articles/fatperspective.html. Accessed 2/15/08.