Dangers of a Low Fat Diet

The low-fat diet craze became popular in the 1970s after engineer Nathan Pritikin appeared on "60 Minutes" touting the success of his dietary approach. Pritikin was diagnosed with heart disease at a young age, and decided to change his diet. His theory, later labeled the "lipid hypothesis," claims that dietary fat, especially saturated fats and fats high in cholesterol, are to blame for America's No. 1 killer, heart disease. In the subsequent years, however, his hypothesis has come under greater scrutiny, and more research has been done on the important role of certain fats in the diet.

Dietary Fats

• Fats, also known as lipids, are an essential part of the human diet. MedicineNet.com defines fat as follows: "along with proteins and carbohydrates, [fat is] one of the three nutrients used as energy sources by the body. The energy produced by fats is 9 calories per gram."

  Fats are an efficient source of energy, providing more than twice the number of calories as proteins or carbohydrates---so a little goes a long way. In addition to providing energy, fats are also involved in the regulation of hormones, help support cell membranes and are needed for the body to assimilate the four fat-soluble vitamins: A, D, E and K.

Unsaturated Fats

• Unsaturated fats have fewer or no hydrogen bonds compared to saturated fats. There are two main types of unsaturated fats: polyunsaturated (which contain two or more carbon bonds) and monounsaturated (which contain only one carbon bond). Because the body breaks down the carbon/hydrogen bonds in fats to produce energy, unsaturated fats provide less energy than saturated fats.

  Unsaturated fats also have a lower melting point than saturated fats, and tend be be liquid at room temperature. For this reason they are less stable, and can become rancid quickly, particularly when heated to high temperatures. Examples of unsaturated fats include olive oil, soy oil, canola oil and safflower oil.

Saturated Fats

• Saturated fats, simply put, are more "saturated" with hydrogen atoms. They are used in cell membranes and support other structures in the body. The heart, for example, is surrounded by a protective layer of saturated fat.

  Saturated fats will stay solid at room temperature. For this reason, it was once believed that plaque buildup in the arteries, called atherosclerosis, was made of saturated fat. (It should be noted that the human body is much hotter than room temperature.) Experts now recognize that the plaque buildup in the arteries is actually composed of calcium and cholesterol. This buildup occurs over time when there is damage to the arteries, either from stress, toxins (such as those found in cigarette smoke) or raised insulin levels.

Cholesterol

• There is a common misconception that cholesterol is fat. Cholesterol is an alcohol-based hormone (hence the suffix "sterol"), and is manufactured in the liver. It is carried through the bloodstream via proteins. Low-density lipoproteins carry cholesterol molecules from the liver into the bloodstream, where they are then delivered to and used by various cells in the body. Meanwhile, high-density lipoproteins carry excess cholesterol molecules back to the liver, where they are turned into bile salts.

Deficiencies Caused by a Low-Fat Diet

• Becase fats are an essential macronutrient and perform necessary functions in the body, a diet low in fat can cause dietary deficiencies. These deficiencies are due, in part, to the lack of fat needed to absorb the fat-soluble vitamins. Some common problems associated with a diet that is too low in fat include fatigue and weakness, depression, poor concentration, hormonal imbalances and metabolic disorders.

  Another problem with the Pritikin lifestyle is its emphasis on carbohydrates. Because many animal products contain fat, people on a low-fat diet avoid protein sources such as meat, eggs, fish and dairy products. This can cause protein deficiencies. People following a low-fat diet plan will certainly lose weight, but at a great cost. The weight loss is the result of severe calorie restriction and can lead to muscle wasting due to lack of dietary protein.

Safe Alternatives

• Because fat-free diets have became so popular, many fat-free products are marketed as healthy alternatives. While both saturated and unsaturated fats are used by the body, trans-fats are not.

  As a rule of thumb, eat foods---including fats---that are found in nature. Avoid chemically altered or processed foods. And avoid many "fat free" products, as they often have sugar or other chemicals added to compensate for flavor.

  For example, some people use margarine or other hydrogenated oils as alternatives to butter. Margarine is made by adding hydrogen to vegetable, soy or canola oil. Nickel particles are then added to stabilize the mixture. It is put into a high-pressure reactor where it undergoes extreme temperatures. The result is a rancid, gray solution. Emulsifiers are added, the mixture bleached, and then dyed a more appetizing color.

  In other words, margarine is not a safe alternative to butter, so enjoy a slather of the creamy, natural spread on your toast.