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Fats are also called lipids. They are a group of chemical compounds that contain
fatty acids. Chemically fats are called triglycerides because the fat molecules are composed of a backbone
molecule of glycerol to which three fatty acids are attached.
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Carbohydrates |
4 kcal/g* |
Fat |
9 kcal/g |
Protein |
4 kcal/g |
*kcal/g is kilocalories per gram. Sometimes the term Calories/g is also used with “C” in
uppercase. Both are correct and 1 kcal = 1 Cal. When we loosely say 1 Calorie, actually we mean 1 kilocalorie. |
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Energy is stored in the body mostly in the form of fat because of its high
energy density in comparison to carbohydrates (see the table above). Fat is also needed in the diet to
supply essential fatty acids that are substances essential for growth but which body is not able to produce.
The terms fat and fatty acids are frequently used interchangeably.
We saw in the table above that 1 gram of fat gives us 9 Calories—more
than twice the calories given by the same amount of carbs or protein. For disease control less is better
in case of fats of certain types—for example saturated and trans-fats. There are several categories
of fats: The good, the bad and the ugly! There are saturated, unsaturated fats and also trans-fats. There
are essential and non-essential fats when viewed from nutritional angle.
There are three main categories of fatty acids: saturated, monounsaturated
and polyunsaturated. Fatty acid molecules are chains of carbon atoms with hydrogen atoms attached to
the carbon atoms.
- Saturated fats
- Polyunsaturated fats (Omega-3, Omega-6)
- Monounsaturated fats (Omega-9)
- Trans-fats
All natural fats that we eat including animal fats and plant based fats are
a mixture of all the three categories mentioned above and usually dominated by one category.
When all carbon atoms are saturated by single bonding with hydrogen atoms,
as well as with other carbon atoms, the fatty acid is called saturated. For disease control, and health
maintenance, one should avoid saturated fats because they promote atherosclerosis (formation of plaque
on the inner walls of the arteries). When arteries of the heart (coronary arteries) get clogged, the
blood supply to the heart will be affected leading to heart attack. Read more about heart
disease…
Saturated fats should not exceed 10% of your total daily calorie intake. Animal
fats are the major sources of saturated fats. Vegetarianism is therefore health-promoting.
In a fatty acid chain, if there is a carbon-carbon double bond due to absence
of two hydrogen atoms, it is called mono-unsaturated fatty acid (MUFA). For disease control, and
health maintenance, one should consume MUFAs in place of saturated fats. MUFAs are heart friendly.
Oleic acid is present in all foods that contain fat. Due to the presence of
the double bond at the center of the oleic acid molecule, it is capable of maintaining the critical nature
of fluidity of the membrane matrix of body cells.
Formation of foam cells along the arterial walls is an important stage in the
development of atherosclerosis (plaque). Oxidized LDL cholesterol helps transform the macrophages (types
of cells) into foam cells. Oleic acid resists this process and thus retards the process of atherosclerosis.
Oleic acid is therefore heart-healthy.[1]
Oleic acid is not an essential fatty acid because body can transform stearic
acid into oleic acid
1. Anonymous. How monounsaturates may save arteries. Science News June 9, 1990:367.
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Fats For Health And Disease Prevention