By Alwyn Cosgrove
How do we actually lose fat? What do we mean by fat ¡§burning¡¨?
Here¡¦s a
very simple, (dumbed down) explanation of what actually goes on to create a fat
loss effect.
The key concept that trainers and physiologists have shoved down our throat for years is that it¡¦s all about calories in vs calories out. This is true ¡V for weight loss - but it¡¦s not the whole truth for fat loss¡V there are a number of protective mechanisms that the body has in place, called rate limiting steps to prevent fat being lost.
On a very basic level - Fat ¡§burning¡¨ is essentially a two step process.
The first step is mobilization. How do we get actually fat out of the fat cells so that we can subsequently use it as a fuel source?
Fat mobilization is governed essentially by levels of a hormone known as hormone sensitive lipase or HSL (you can forget the name as there wont¡¦ be a test). It¡¦s an oversimplification but basically the higher the HSL levels, the higher the fat mobilization.
How do we get higher HSL? Increase catecholamine levels (specifically adrenaline).
How do we do that? Exercise. Particularly high intensity exercise.
But HSL is also limited by insulin. High insulin levels = low HSL levels = low fat mobilization.
So a great strategy for part one is low insulin levels (from diet and training), plus high catecholamines (through intense training).
Part two of the process is transport and oxidation.
If HSL levels are high - fat cells break down into free fatty acids (FFA) which circulate in the blood and eventually end up in a muscle (which needs energy) where they can be burned off in the mitochondria (this is the ¡¥powerhouse¡¦ of the cell that your high school biology teacher kept going on about).
But there¡¦s another rate limiting step here. Transporting the FFA into the mitochondria where it can be burned off. That transport is controlled by carnitine levels.
If carnitine levels are high - fat transport is high.
Think of carnitine like passport control officials.
If you get off a plane with 500 other passengers and there is one official at passport control - it¡¦ll take a long time to get through. If there are 500 officials - then you go through quickly and can leave the airport. (Leaving the airport is the equivalent of fat being burned off). The more officials (carnitine) the easier the process.
So how do we ramp up carnitine levels? Well - again we have a rate limiting step. If muscle glycogen is high then carnitine levels are low.
So if we reduce muscle glycogen through metabolic work ¡X we have the optimal
fat oxidation state. Therefore high intensity glycogen depleting exercise is a
the tool of choice here.
High levels of fat mobilization + High levels of fat
oxidation = Accelerated fat loss.
So if you figure out how to integrate all those steps, and circumvent each rate limiting step - you¡¦ll find that fat loss is simple ¡K..
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About the Author: Mike Roussell is an author and nutrition doctoral student at Pennsylvania State University. Mike writings can be found in Men's Health and Men's Fitness and Ironman Magazines in addition to the internet's largest bodybuilding and fitness website - T-Nation.com His Warp Speed Fat Loss system is a complete Done-for-You A-Z Fat Loss Blueprint. You can learn more at WarpSpeedFatLoss.com Warp Speed Fat Loss is a complete 28 day diet and training system crafted to help you lose 10,15, or 20lbs of body fat in just 28 day. To start losing weight fast visit Warp Speed Fat Loss. |