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Dietary Fats: 101
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As if the volumes of conflicting information on dietary fats were not already confusing enough, a recent report from Fox News claims that dietary fat can actually make you stupid and lazy! (That doesn't exactly sound "fair and balanced"). Conversely, you may also have heard the claim that to lose fat, you must eat fat. (see article in Nourished Magazine here). While there is enough science on both sides to see each point of view, let's review some dietary basics, including the definition of dietary fat, before making a decision.
Fact #1
Fat is a macro-nutrient (the three major components of our diet). Along with carbohydrates and proteins, fats (also called lipids) are required by the human body to sustain life and normal metabolic function. At more than twice the caloric value as a carbohydrate gram or protein gram, one gram of fat goes a long way. Fats also take up to twelve hours to break down in the digestive system, providing a long-term source of energy. In comparison, carbohydrates break down in less than four hours (1/2 hour for simple sugars), and proteins generally take six to eight hours to completely break down.
Fats are required in the production and regulation of hormones, including: leptin (which tells the body when to eat and when it is satisfied), and adenopecton (involved in both glucose and lipid metabolism). Fats are also required to assimilate the fat-soluble vitamins: A, D, E, and K, and are also needed for the synthesis of certain minerals, including calcium and magnesium.
Fact #2
Not all fats are the same. We've all heard the reports on all the different types of fats, mono-unsaturated, poly-unsaturated, saturated and trans-fats. Many claim that the fats which come from animal products, namely saturated fats, are the "bad" fats and cause high cholesterol and heart disease. This theory, for which there is ample research both for and against, is known as the lipid "hypothesis". Supporters of the lipid hypothesis further assert that saturated fat is responsible for the plaque build up of the arteries known as atherosclerosis. This is how saturated fat has supposedly earned the reputation that it "causes heart disease". However, this theory is slowly beginning to unravel, as newer research has determined that the plaque within the arteries is not made of saturated fat, as once believed, but is a buid up of the arterial wall from excess cholesterol. To clarify, cholesterol is not fat, but a hormone produced by the liver.
So why would the body produce excess cholesterol? It is a simple biological response to over production of insulin. The pancreas produces insulin to regulate blood sugar. When there is excess sugar, higher levels of insulin are produced. Excess insulin can actually weaken arteries over time. The body's response to this is to produce more cholesterol, which lines the weakened arterial walls. It is our own built in safety mechanism. So the real culprit here is the excess sugar, not fat, or even cholesterol. The liver is only doing its job after all!
The main difference between saturated fat and unsaturated fat is the concentration of hydrogen atoms. Saturated fats are densely populated (or "saturated") with hydrogen. While, unsaturated fats have a lower concentration of hydrogen atoms. Both are used by the body. Trans-fats however, are not found in nature. Many experts have serious concerns about the consumption of hydrogenated, or trans-fats.
Fact #3
The hydrogenated and synthesized fats that are often peddled as "health foods" are not only unhealthy, but biologically dangerous for consumption. Recent studies show that trans-fats are linked to certain cancers. However, we have been told that the unsaturated fats found in vegetable oils and margarine are the "good" fats. Let's explore this.
Have you ever wondered, for example, how margarine is made? Margarine is made by a process called hydrogenation. It begins as soy, corn, or canola oil, and is mixed with a catalyst (usually metal particles such as nickel oxide). Hydrogen gas is added, and then it is put into to a high pressure, high temperature reactor. The result is a rancid, grey-ish colored mixture. Emulsifiers are added for texture, and then it is bleached, and finally dyed to give it a more appetizing appearance. Lastly, it is poured into tubs and sold in the market with the heart healthy label we are all familiar with. Looks certainly can be deceiving!
Fact #4
A diet low in fat or devoid of fat will cause serious deficiencies. This is associated with the #1 myth - fat is bad. As explained in the first fact, fat is a necessary component of the diet. We learned that it is responsible for proper brain function, hormone production, energy production, among other things. If you understand this basic fact, the next question you may want to ask yourself is, "what happens to the body on a low-fat diet?"
A diet low in fats will ultimately show signs of deficiency, or malnutrition. Some common conditions that are associated with lack of proper dietary fat include:
Fatigue
Depression
Hormonal imbalance
Memory loss
Loss of concentration
Metabolic disorder
These result from either hormone imbalance or vitamin deficiencies from the lack of fat present in the diet.
Fact #5
The fat you consume is not necessarily the fat stored in the cells of your body. When we see someone who is overweight or even obese, the assumption often is that they have a high-fat diet. This assumption is false. Carbohydrates, which are broken down into simple sugars, are converted into glucose, which then can be used immediately for energy. The excess glucose which is not needed, is then converted into fat, and stored in the cells for future use. In other words, the fat in our fat cells, most likely, was at one time sugar.
In addition, the presence of sugar in the system stimulates the production of insulin. As previously mentioned, insulin is the hormone responsible for the regulation of sugar in the bloodstream. However, when there is excess sugar, the body is forced to continually produce insulin to keep blood sugar levels from rising. Overtime, with excessive sugar and carbohydrate consumption, the pancreas is unable to keep up, and the body develops insulin resistance. This sad situation is more commonly known as Type II, or adult onset diabetes.
Of course not all overweight individuals have Type II diabetes, and not all those with Type II diabetes are overweight. In the same token, we cannot assume someone who is overweight simply eats too much fat. Everybody is different, and we cannot lump everyone with a certain physical condition under one label.
Good fat/bad fat?
The bottom line is fat is a necessary part of a healthy, balanced diet. And, while there is a big difference between saturated and unsaturated fats on a molecular level, the fats found in nature (including saturated animal fats) are readily usable by the human body, and are a valuable part of proper nutrition. If you are concerned about fat consumption, then limit your intake of trans-fats (such as margarine), which have known health risks.
For more information on the health benefits of dietary fat, read:
Nourishing Traditions, by Sally Fallon and Mary Enig, PhD.
and
The Schwarzbein Principle, by Diana Scwarzbein, MD
SOURCES:
FOX: http://www.foxnews.com/story/0,2933,539158,00.html
Nourished magazine: http://nourishedmagazine.com.au/blog/articles/eat-fat-lose-fat-by-sally-fallon-and-mary-enig
Science daily: http://www.sciencedaily.com/releases/2004/04/040422224153.htm
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