In this article I will cover body fat. After you finish reading it you will know exactly what it is, how it is absorbed by your body and how it is broken down and used as an energy source! Since my site is about creating permanent fat loss, the more you understand about fat, the easier it will be for you to design an effective weight loss program for yourself!
Fat, or adipose tissue, is found in several places in your body. Most of your fat (subcutaneous) is found underneath your skin. But there is also some fat on top of the kidneys, in the liver and very small amounts in your muscles.
Women tend to carry fat in their breasts, hips, waist and buttocks. Men tend to carry fat in their chest, abdomen and buttocks. This is the main reason why men and women have different body shapes.
Generally fat cells do not generate after puberty, and as your body stores fat, your fat cells simply get bigger in size! The only exception is when there is a significant weight gain, or after liposuction. However, althoughliposuction surgery is a fast and effective method to eliminate fat, it is also important that recommendations, including diet, are strictly followed for a faster healing and improved long term results.
Resorting to cosmetic surgeries such as liposuction is not really a bad thing, but a patient of such surgery should understand how to be keenly cautious and careful because the liposuction recovery time is crucial to getting the best desired result.
Body fat tissue is made up of fat cells. You can think of a fat cell as a tiny balloon that holds a tiny drop of fat!. Fat cells are large cells that have very little cytoplasm, with only 15% of the cell volume, and a large fat droplet that makes up 85% of the cell volume.
How Fat Is Transported & Absorbed
When you consume food that contains fat, it goes through your stomach and intestines. In the intestines the large fat droplets get mixed up with bile salts from the gall bladder in a process called emulsification.
These bile salts break up the large fat droplets into several smaller droplets called micelles, increasing the fat’s surface.
The pancreas then secretes enzymes called lipases that attack the surface of each micelle and break the fats down into their parts, glycerol and fatty acids. These parts get absorbed into the cells lining the intestines.
In the intestinal cell, the parts are reassembled into packages of fat molecules (triglycerides) with a protein coating called chylomicrons. Chylomicrons are one of the five major groups of lipoproteins that enable fats to move within the water based solution of the blood stream.
Since the larger fats do not attract as many water molecules as many smaller molecules would, while the fats are being transported in the lymph or blood, your body uses the chylomicrons to accomplish this task.
The chylomicrons are released into the lymphatic system, but they do not go directly into the bloodstream because they are too big to pass through the wall of the capillary.
The lymphatic system eventually merges with the veins, at which point the chylomicrons pass into the bloodstream. Since the fat molecules are too big to easily cross the cell membranes, they are broken down into glycerol and fatty acids.
How Fatty Acids, Amino Acids & Glucose Are Stored As Body Fat
When you consume food the presence of glucose, amino acids or fatty acids in the intestine stimulates the pancreas to secrete a hormone called insulin. Insulin acts on many cells in your body, especially those in the liver, muscle and fat tissue.
Insulin instructs the cells to do the following:
1) absorb the glucose, fatty acids and amino acids.
2a) stop breaking down glucose, fatty acids and amino acids
2b) stop breaking down glycogen into glucose
2c) stop breaking down fats into fatty acids and glycerol
2d) stop breaking down proteins into amino acids
3a) start building glycogen from glucose
3b) start building fats (triglycerides) from glycerol and fatty acids
3c) start building protein from amino acids
The fatty acids are then absorbed from the blood into the fat cells, muscle cells and liver cells. In these cells, under the stimulation by insulin, fatty acids are made into fat molecules and stored as fat droplets!
The liver stores the glucose in the form of glycogen and releases it into the bloodstream to provide our body with energy, whenever this is necessary.
Your blood stream is like a interconnected conveyor belt that takes the necessary nutrients to the body parts that need them. Once the glucose runs out, only then body fat takes over as an energy source!
By the way, harnessing energy by burning fat is referred to as ketosis.
It is also possible for the body fat cells to take up glucose and amino acids, which have been absorbed into the bloodstream after a meal, and convert those into fat molecules.
The conversion of carbohydrates or protein into fat is 10 times less efficient than simply storing fat in a fat cell, but our bodies can do this.
For example, if you have 100 extra calories in fat (11 grams) floating in your bloodstream, fat cells can store it using 2.5 calories of energy.
If you have 100 extra calories in glucose or amino acids (25 grams) floating in your bloodstream, it takes 23 calories of energy to convert the glucose or the amino acids into fat and store them.
This process is inefficient, and given a choice, your fat cell will always grab the fat because it is simply much easier for your organism to store.
How Body Fat Is Broken Down
When you are not eating, your body is not absorbing food. If it is not absorbing food, there is very little insulin in the bloodstream.
However, your body is always using energy; and if you’re not absorbing food, this energy (calories) must come from the internal stores of complex carbohydrates, proteins and fats.
Under these conditions, various organs in your body secrete hormones: the pancreas secretes glucagon, the pituitary gland secrets the growth hormone and the ACTH hormone, the adrenal gland secretes epinephrine and the thyroid gland secretes the thyroid hormone.
These hormones act on the cells of the liver, muscle and body fat tissue, and have the opposite effects of insulin. When you are not eating, or you are exercising, your body must draw on its internal energy stores.
Your body’s prime energy source is glucose. When we eat, the glucose and sugar harnessed from carbohydrates are the first fuel sources ou body uses. In fact, some cells in your body, such as the brain, can get energy only from glucose.
The first line of defense in maintaining energy is to break down carbohydrates, or glycogen, into simple glucose molecules, this process is called glycogenolysis.
Next, your body breaks down fats into glycerol and fatty acids through a process called lipolysis.
The fatty acids can then be broken down directly to get energy, or can be used to make glucose through a multi-step process called gluconeogenesis. In gluconeogenecis, amino acids can also be used to make glucose.
In the body fat cell, other types of enzymes called lipases work to break down fats into fatty acids and glycerol. These lipases are activated by various hormones, such as glucagon, epinephrine and the growth hormone.
Triglycerides are made of glycerol and three fatty acid chains. When they receive the signal from the lipases to exit the fat cells, the triglycerides break up into their respective components and enter the bloodstream for use.
The resulting glycerol and fatty acids are released into the bloodstream, and travel to the liver through the blood. Once in the liver, the glycerol and fatty acids can be further broken down for energy and some of the fatty acids move to the muscles that can use them for energy as well.
Once inside the mitochrondia, or power source, or muscle or liver cells, the components of the glycerol and fatty acids are shuffled and reshuffled to harness their energy potential, producing heat, water, carbon dioxide and adenosine triphosphate (ATP).
Adenosine triphosphate (ATP) is a complicated biochemical process that we use to store and use energy. ATP hauls potential energy in its molecular bonds for use when we exercise like cellular carb loading. The water exits our bodies as sweat and urine, and we exhale the carbon dioxide.
What all this boils down to is that in order to create the body of your dreams, reach your ideal weight, and achieve permanent fat loss you must work with you body and provide everything it needs to function properly.
In our bodies, fat is the primary form in which we store excess long-term energy. It is not readily available as an energy source like carbohydrates, and is meant to be used to sustain us in times of starvation, whether it is self-imposed or otherwise.
This is one of the main reasons why it is so difficult to lose body fat, especially when your drastically lower your daily calorie intake.
As soon as your body senses a sharp drop in your daily calorie intake, instead of burning unwanted body fat, as most people would like, it triggers the starvation response and starts to conserve its energy.
Converting your muscle to glucose and burning it as an energy source, is one of the ways your organism lowers its calorie burning ability, getting ready for starvation.
Your body can’t tell the difference between low calorie dieting and the beginning of starvation. As soon as your daily calorie intake drops below a certain point, your body will adjust to this new calorie intake by burning your muscle.
The other reason why it is difficult to lose unwanted body fat, is that our organism views body fat as a source of protection, and because of this, it is reluctant to give it up easily.
Throughout our bodies, fat is a component of cell membranes, it serves as a precursor to a variety of hormone-like substances, acts as an insulator against heat loss, and protects vital organs such as the kidneys and heart.
So if your goal is permanent fat loss, you must move toward this objective very slowly. The ultimate long term fat loss strategy is losing one to two pounds of body fat per week.
If you attempt to lose much more, your body will resist and fight you the whole time. In the end your body will always win by triggering its defense mechanisms and forcing you to eat what it needs to function properly!
The five most important things you can do to reach you ideal body fat percentage are the following:
1) consuming the optimum daily calorie intake for your goal
2) using the right nutrient ratios for your body type
3) using an effective meal frequency/timing approach
4) eating natural unprocessed carbs, protein and dietary fat
5) drinking plenty of water on a daily basis
If you follow these fundamentals of proper nutrition and use exercise on a regular basis, you will reach your ideal body fat percentage, and will become a proud owner of a lean, healthy body!