Week 12 – Types of Calories – Fats

If common nutrition thinking were a Hollywood movie, fat would be the villain, probably scheming along with complex carbohydrates, to keep us all overweight. Even though portraying fat as the villain is a great marketing tool to sell food, it is far from the truth. The truth is that fat is extremely misunderstood by the general public. For starters, the term ‘fat’ is not really appropriate. There is a disconnect between the biological definition of fat and how the term is used in nutrition. The biological definition of fat is a fatty acid that is solid at room temperature. If a fatty acid is liquid at room temperature it is referred to as an oil. However, in the nutrition world, and as far as the principles in The Weight Equation are concerned, both are considered ‘fats’ regardless of their state at room temperature.

As discussed above, the ‘term’ fat does not mean the same thing to a biologist as it does to a nutritionist. The biologically appropriate term for ‘fat’ is ‘lipid’. All fats are lipids, but not all lipids are fats as some lipids are oils. After this blog entry the term ‘fat’ will be used synonymously with the term ‘lipid’ as it is in the nutrition world.

Lipids serve three incredibly important functions in your body

1) They provide a medium to store energy
2) They form membranes around your body cells
3) They are used by your body to compose hormones and vitamins

The Weight Equation is primarily concerned with the first function listed above, but keep in mind that if your body fat percentage ever drops too low, you will start to have trouble producing hormones and vitamins and your cells will have difficulty maintaining their functions. A better discussion about body fat percentage will take place in a subsequent blog entry.

Fatty Acid Chains

If you’ve followed the blog up to this point you know that complex carbohydrate molecules are chains of hundreds of monosaccharides and Proteins are long chains of amino acids. Similarly, lipids are made by combining many fatty acid chains together. These fatty acid chains are typically 10-20 carbon atoms long and as seen below, they always have a carboxyl group at the end(C=O-OH). There are two types of fatty acids: saturated fatty acids and unsaturated fatty acids. You’ve probably heard the terms saturated and unsaturated fats before. Food labels even distinguish between the two. Have you ever wandered what the difference is?

Fatty Acid Chains

Notice the two extra hydrogen atoms in the saturated fatty acid chain. This is where the name comes from. The chain is “saturated” with hydrogen atoms. Saturated fatty acid chains are solid at room temperature and referred to as ‘fats’ while unsaturated fatty acid chains are liquid at room temperature and referred to as oils. As shown above, unsaturated fatty acid chains have a double bonded carbon in the middle taking the place of two hydrogen atoms. This double bond twists the chain enough so that unsaturated chains have a difficult time getting close together and therefore act like a fluid. The saturated chains are straighter because there isn’t a double bond and they can get closer to one another and stick together, acting like a solid at room temperature. When fatty acids are metabolized, your body breaks apart the many energy rich C-H bonds in the chain.

Ever heard the term, ‘Omega-3 Fatty Acid’? If you pay attention to nutrition at all, I’m sure you have! High amounts of it are found in nuts and fish oils AND according to the latest Stanford study, it’s GREAT for you. Have you ever wondered what the heck it actually is though? Of course not, I’m the only weird guy who is curious about these things right?!? Well just in case I’ve piqued your interest, an Omega-3 Fatty Acid is simply an unsaturated fatty acid chain with the first double-bonded carbon atom three spots from the end of the chain. The position of 3rd from the end is where the name Omega-3 is derived. What position is the double-bonded carbon in the unsaturated fatty acid chain pictured above? You earned extra points if you answered “8th position” out loud with no one else around 😉 The fatty acid chain shown above is an Omega-8 Fatty Acid. Now you know, and knowing is half the….well you’re probably to young to remember the rest of that line anyway.

Triglycerides

Triglycerides are another chemical you’ve probably heard of but never really understood exactly what it was. This chemical is extremely important to The Weight Equation as this is the chemical your body produces to store energy. In other words triglycerides are body fat. Most people using The Weight Equation are working towards a lower body fat percentage and the goal is to break up and metabolize a large percentage of the triglyceride molecules located in cells all over your body. The specific location of triglyceride storage in your body is genetically predetermined. Typically, triglyceride storage is concentrated in the abdominal area for men and the hip area for women. Unfortunately there is nothing you can do, short of surgery, to target a specific area for breaking up triglyceride molecules. When your body needs to tap its energy reserves(IE you require more calories than you’ve consumed), it breaks up triglyceride molecules equally from all cells in the body that store them. This process is known as ketosis and if you’re trying to reduce your body fat percentage, ketosis is the goal.

When your body takes in more calories than it burns it creates, or synthesizes, triglyceride molecules by combining a glycerol molecule(shown below) with three individual saturated fatty acid chains(shown above). The “tri” in triglyceride comes from the “three” saturated fatty acid chains linked together by the glycerol molecule. This process is illustrated below. As you can see, three H2O(water) molecules are released in this process which is called dehydration synthesis.

Triglyceride Synthesis

Phospholipids

I won’t spend a lot of time discussing phospholipids because they are not a factor in The Weight Equation but they are very interesting. Phospholipids serve the other two functions of fats in the body: They compose cell membranes and are used in the production of hormones and vitamins. Phospholipids are structurally similar to triglycerides except one of the fatty acid chains is replaced by a chemical containing phosphate, which is where it gets the prefix “Phospho”.

Common foods with high amounts of fat are:

Vegetable Oil
Certain Cuts of Meat
Cheese
Avocado
Nuts

The most important thing to know about protein when applying The Weight Equation is:

1 gram of protein contains 9 calories

References:
http://www.mckinley.illinois.edu/handouts/macronutrients.htm
http://courses.washington.edu/conj/membrane/fattyacids.htm
http://www.livestrong.com/article/351331-dehydration-synthesis-in-lipids/
http://www.sportsci.org/encyc/adipose/adipose.html

Please enjoy the powerful information I am sharing in this blog but remember that I am NOT a nutritionist or a professional. I am simply passionate about the subject. Please consult with your doctor and nutritionist before implementing any diet

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