Of the three main nutrients (fat, protein, carbohydrate), fat is the most complex and interesting and gives us the most latitude to improve our nutrition.
Protein consists of long chains of amino acids which fold into useful shapes to provide structure and function such as enzymes and muscles. There are 21 different amino acids and these can be assembled into countless combinations to form complex shapes. However, from the nutrition standpoint, all protein is pretty much the same. Whatever the source of protein, our digestive system disassembles the long chains into individual amino acids which are then absorbed into the blood stream. Our body then uses these amino acids to build the proteins it needs.
Carbohydrates are also simple. They are short or long chains of sugars. The digestive system breaks these down into simple sugars; they are absorbed and used as fuel.
However, fats are more complex. There are many different kinds of fats and they are metabolized differently.
Since we already have fuel in the form of sugars, why do we need fat? Can't we just store sugar or starch? The answer is that sugar and starch are water soluble and are osmotically active so in order to store significant amount of fuel, we would need lots of molecules and each of these molecules attracts water. We would literally bloat up with water.
Fat has the advantage in that it is not water soluble so you can store lots of fuel in a glob of fat and not have to worry about attracting water.
Fats are long chains of hydrocarbons with oxygen molecules at crucial locations which repell water. These are large molecules with lots of different shapes and variations. Animal fat has more hydrogen bonds and is said to be "saturated". Vegetable fats are "unsaturated". Cholesterol is a special type of saturated fat.
We know from lots of research that the body handles different kinds of fat differently and that when you eat large amounts of animal fat (saturated fat), this leads to high cholesterol and high LDL. This is associated with heart disease, high blood pressure, diabetes, stroke and other medical problems.
Trans fat has been in the news recently because they have been banned by the FDA. Trans fats are a type of synthetic fat manufactured by taking vegetable oil and adding hydrogen. Unfortunately, it took many years of research to confirm that these synthetic fats are as bad for you as saturated fat. Unfortunately, the food industry has come up with new synthetic replacements (interesterification) which are not proven safe and show some of the same problems (increase in LDL and increase in blood sugar and insulin) as trans fat. I fear we may confirm that these are also dangerous years from now.
Vegetable fat (unsaturated) does not tend to cause these problems and should be preferred. Olive oil and peanut oil are mono-saturated fats which are also known to be healthy. Fish oil (omega fatty acids) are also know to be beneficial and protective from heart disease.
Protein consists of long chains of amino acids which fold into useful shapes to provide structure and function such as enzymes and muscles. There are 21 different amino acids and these can be assembled into countless combinations to form complex shapes. However, from the nutrition standpoint, all protein is pretty much the same. Whatever the source of protein, our digestive system disassembles the long chains into individual amino acids which are then absorbed into the blood stream. Our body then uses these amino acids to build the proteins it needs.
Carbohydrates are also simple. They are short or long chains of sugars. The digestive system breaks these down into simple sugars; they are absorbed and used as fuel.
However, fats are more complex. There are many different kinds of fats and they are metabolized differently.
Why fat?
Osmotic pressure.Since we already have fuel in the form of sugars, why do we need fat? Can't we just store sugar or starch? The answer is that sugar and starch are water soluble and are osmotically active so in order to store significant amount of fuel, we would need lots of molecules and each of these molecules attracts water. We would literally bloat up with water.
Fat has the advantage in that it is not water soluble so you can store lots of fuel in a glob of fat and not have to worry about attracting water.
Fats are long chains of hydrocarbons with oxygen molecules at crucial locations which repell water. These are large molecules with lots of different shapes and variations. Animal fat has more hydrogen bonds and is said to be "saturated". Vegetable fats are "unsaturated". Cholesterol is a special type of saturated fat.
Digesting all of this...
Fats that we eat are handled differently than protein or carbohydrates. Fats are broken down only into triglycerides which are absorbed directly into the blood stream. Therefore, the types of fat you eat make a difference since they are absorbed directly into the blood. A common test for "blood lipids" is to measure these in the blood. They can be roughly separated into "high density lipoproteins (HDL)", cholesterol and "low density lipoproteins (LDL)". There are many different kinds of fatty acids and these are only the large groupings.We know from lots of research that the body handles different kinds of fat differently and that when you eat large amounts of animal fat (saturated fat), this leads to high cholesterol and high LDL. This is associated with heart disease, high blood pressure, diabetes, stroke and other medical problems.
Trans fat has been in the news recently because they have been banned by the FDA. Trans fats are a type of synthetic fat manufactured by taking vegetable oil and adding hydrogen. Unfortunately, it took many years of research to confirm that these synthetic fats are as bad for you as saturated fat. Unfortunately, the food industry has come up with new synthetic replacements (interesterification) which are not proven safe and show some of the same problems (increase in LDL and increase in blood sugar and insulin) as trans fat. I fear we may confirm that these are also dangerous years from now.
Vegetable fat (unsaturated) does not tend to cause these problems and should be preferred. Olive oil and peanut oil are mono-saturated fats which are also known to be healthy. Fish oil (omega fatty acids) are also know to be beneficial and protective from heart disease.
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