The Story of Fat Loss: Fat Mobilisation

So in the last post I elaborated on fat metabolism. There is a ton of stuff we can do to speed up fat metabolism like reducing toxicity, improving digestive function, getting to bed on time - just stuff that improves your biochemistry. The area I chose to focus on was increasing muscle - NOT bodybuilding and not to make you bulky - but to improve you resting metabolic rate. You can read more here.

BUT WAIT!!! Theres more....

Fat metabolism is one thing. Fat mobilization is another.

Burning fat essentially involves 3 steps - mobilization, transportation and oxidation.

Step 1 - Mobilization, involves getting fat out of the fat cells. You need to get it out of the cell and into the muscle to burn it as energy.

You can understand your bodies reluctance to give up fat stores. Evolution designed us to preserve energy. Therefore, because of evolution, our bodies don’t want to burn fat or lose weight. Plus we like food and keep putting sugary easily absorbable energy back in the system so it makes it difficult!

Therefore I’m gonna level with you - to mobilize fat we do actually need a calorie deficit. A shortage of fuel means the body draws on energy stores. This doesn’t mean a 500cal diet, there are smarter ways...

Please first bear this in mind, our body has three energy stores - glycogen (from carbs), lean muscle (from protein) and fat. (this is a really simplistic explanation and perhaps its a little bit more complicated than this, but I like the simple explanation so we’ll go with that for the time being..)

Let’s cut to the chase, glycogen (starches & sugar - carbs) is the easiest place for your body to get energy. Therefore, for the most efficient way to target body fat you will need to keep glycogen low.

To do this you can use a combination of diet and intense exercise. This will use glycogen - this means the body cant do the lazy option and get it from there.

To further support this process and to fully support fat metabolism and increase your resting metabolic rate you will need to develop and/or maintain muscle and keep it active. (ala the last post...)

Therefore a reduced carbohydrate diet and intelligently prescribed strength-based training program will shift the body into a fat burning furnace.

Now for the science...

So how do you get the fat out of the fat cell?

To get the fat out the fat cell or to mobilize fat you need to break down triglycerides in the fat cell into free fatty acids to enter the bloodstream.

This happens by maintaining a lower blood sugar. When you maintain a lower blood sugar the hormone glucagon signals to activate hormone sensitive lipase (HSL) and to convert triglycerides into free fatty acids and to transport them to muscles and the liver where they can be burned.

This whole process is limited by HSL. This is referred to as a rate determining step.

A rate determining step (RDS) is the slowest step in any chemical reaction and is similar to the neck of a funnel. (You could stimulate fat-loss with hard exercise and an energy deficit to get fat into blood stream BUT unless you support the process with good nutrition you will be hampered by these RDS's - Hence the need for a fully integrated approach to fat-loss...) Limiting the effects of the RDS’s is the name of the game if we want fast and sustainable fat-loss.

In simple terms, if HSL is low the fat mobilization will be slow. If HSL is high the fat mobilization will be fast. So you can see why increasing HSL is our goal.

To do this we need to increase catecholamine levels in the blood.

So how do we increase catecholamine levels in the blood? Exercise. The more intense the better. Intense exercise elevates catecholamine levels and HSL levels which equals accelerated fat loss.

But wait... There is one other rate determining step to consider. Your body secretes insulin to remove glucose from the bloodstream. HSL can also be limited by insulin.

To lower insulin you MUST keep blood sugar under control. (do you notice a similar theme occurring here?!)

So, regardless of whatever rate determining step the basic strategy is still the same - managing blood sugar and intense exercise is essential for mobilizing fat.

This will keep insulin low and catecholamines high which will lead to HSL being high which will convert triglycerides into free fatty acids to enter the bloodstream to be burnt as fuel...

So what about the transportation and oxidation of fat?

So HSL is high, fat cells breakdown free fatty acids (FFA) which are transported in the blood to muscles to be used as fuel. But another rate determining step (RDS) occurs...

Everything at this stage becomes dependent on carnitine levels. Carnitine transports FFA’s to mitochondria (the powerhouse of cells) where it is burnt. In simple terms, increased carnitine equals increased fat loss, increased carnitine equals increased mitochondria activity.

How do you increase carnitine levels? ANOTHER RDS! (Do you think our body is looking to hold on to this stubborn body fat... remember your body doesn’t want to lose fat!!) Muscle glycogen levels have to be low for carnitine to be high.

So... for optimal fat oxidation we NEED to deplete muscle glycogen through intense exercise (resistance training/ bootcamp/ intervals) and making better choices with food (low carb).

In essence, high levels of fat mobilisation + high levels oxidation = accelerated fat loss

Just to note: waste products occur during all of these processes and are processed through the kidneys. Your kidneys require water to do there jobs efficiently.

If you don’t drink enough water and are dehydrated the burden passes to the liver. The liver is useful in this process because it processes stored fat for energy.

If the kidney is slow in doing its job (due to dehydration) the liver will help out.

While the liver is processing waste products it is less efficient at mobilizing body fat. So... You NEED to be hydrated to burn fat. (This also supports the notion why eating better quality clean food is important to burn fat (i.e. DETOX)

To cut a long story short... Stabilize blood sugar with a reduced carbohydrate diet and do intense exercise such as resistance training or intervals.

Remember, fat loss is simple. It is simple, not easy.