The Fat Fight: Part 3

Part 1 and 2 looked at the purpose of fat, adverse effects of high body fat, why it can be hard to lose and how to go about losing it.

In this installment, we will delve into the science of fat burning.

To recap:

There are three stages from fat leaving a cell to being burned in another cell.

1. Mobilization or Lipolysis - is the process of triglycerides in adipose cells being broken down into free fatty acids

2. Transport - is the free fatty acids being transported in the blood to cells in the body that will convert the fatty acids into the energy your body needs

3. Oxidation - is the actually conversion of the free fatty acid into ATP, which is the body’s fuel.

Mobilization

1. To mobilize fat, you must set up the proper hormonal environment. The most important hormone to keep in mind is insulin. Insulin, as mentioned above, is a storage hormone. Insulin levels increase to lower elevated blood sugar from a meal by signalling the body to store the energy and nutrients in both adipose tissue and muscles. As you may have guessed, to lose fat you want to have low insulin levels. Low insulin occurs when you are in a fasted state (i.e. when it has been a long time since your last meal) or post workout because you have used up your existing blood sugar.

Next on the list is catecholamines (adrenaline), which you want to be elevated because they stimulate your metabolism and increase fatty acid mobilization. You can boost your catecholamines by consuming caffeine or engaging in high intensity exercise.

Higher growth hormone (from here out referred to as GH) and cortisol can help mobilize fat as well. Pushing yourself hard in the gym and feeling the lactic acid burn will release GH. Cortisol, commonly referred to as a stress hormone, is a bit tricky and we must be careful. We do not want to intentionally and chronically stimulate this hormone due to its many negative long term effects. Chronic elevation leads to fat gain, the exact opposite of what you are attempting to achieve! Thus, with cortisol, seek a balance, and make sure you are engaging in plenty of stress relieving activities. In relation to fat burning however, cortisol will be higher naturally upon waking and also after intense exercise.

You want to stimulate an enzyme called HSL, which is responsible for the breakdown of fat cells in the body. Luckily, increasing HSL is as simple as following the steps listed above. HSL will increase when your insulin is low and your catecholamines and GH are high. During exercise and when insulin is low, your body will also produce glucagon. It has the opposite action of insulin, glucagon elevates low blood sugar by instructing your body to release glucose from your liver but it also stimulates mobilization of fatty acids.

Please do not get carried away with this next statement. Assuming you have met the above hormonal requirements and you have created an ideal fat burning environment, then studies have suggested that muscular contractions will increase the localized mobilization and oxidation of fat but only to a very minimal extent. Regarding this idea of localized fat burning, for this to even be remotely effective you would already have be at extremely low body fat levels (like you were preparing for a bodybuilding competition).

Transport

2. To transport, you need to increase blood flow. The free fatty acids are transported in the blood to cells in the body that will convert the fatty acids into the energy your body needs. Think of your circulatory system as your body’s transportation system.

If you look at a map of the United States you will see large interstates, slightly smaller state highways, business routes, and local roads. If you could zoom in closer, you’d see unpaved roads as well. This is similar to your body’s circulatory system. The major veins and arteries are comparable to the interstates highways right on down to the tiny capillaries that are like local unpaved roads. And just as some areas of the country are harder to get to, some areas of your body simply do not received the same amount of blood flow.

This can be an issue, feel the fattest area of your body. Often time, it is cold because blood flow in that area is lacking. To increase blood flow you must actually work the area you are hoping to lose fat from and seek a long term adaptation of increased capillarization. Capillarization is the process of your body building more blood vessels in the target area to facilitate blood flow.

I must remark again, how thankful I am for the way we are designed. Our bodies are made to adapt to our exercise and diet. By training in a way to increase your body’s demand for blood supply to a specific region, you will actually encourage your body to increase and improve the existing capillaries, fantastic!

How do we go about encouraging capillarization and improved fatty acid transport?

This is best done with exercise of a higher volume and intensity. You will want to go for the lactic acid burn as this is a good sign that you are working out intensely enough to stimulate the improvements you desire. Higher repetition (8-12 reps) resistance training while coming close to failure but still using good form combined with shorter rest periods works very well to create the adaptations required for fat burning.

Additionally, sprints performed on a bicycle are excellent as they won’t negatively impact muscular recovery, in fact, they may encourage it if done properly. However, you cannot do both high intensity and high volume all the time because you will burn out, you must be careful to strike a balance. Constant stressful activity will lead to chronically elevated cortisol which has been directly related to increases in abdominal fat.

What about endurance activities?

While endurance activities will certainly get your heart pumping and your blood circulating, they do not produce the growth hormone (GH) needed to stimulate new blood vessel growth.

You have two main pathways to generate energy; anaerobic and aerobic. By definition, anaerobic is when you are deprived of oxygen and a byproduct of that energy pathway is lactic acid and GH. The aerobic pathway, again, by definition, uses oxygen and is not very beneficial to producing GH. Endurance activities, what we typically call “cardio”, use the aerobic pathway and are not the activity of choice to tap into hard to lose fat.

“Wait a minute,” you may say, “whether I am lifting weights or running, I still use oxygen. I am breathing the whole time, what gives?”

Great question, which pathway your bodies utilizes is based on whether it has ENOUGH oxygen at a given moment to fuel the aerobic pathway. If the exercise intensity is high enough and you do not have enough incoming oxygen, then your body creates energy through the anaerobic pathway. You may be breathing during your entire set of squats, but the demand on your thighs is so high that they are not able to utilize the aerobic system to provide the ATP you need to complete the set. All your body wants to do is avoid being crushed by the weight on your back, it does not know whether you were hoping to do aerobic or anaerobic activity that day. It simply responds to the demands you place on it.

Additionally, performing endurance activities too often will chronically raise cortisol levels. High cortisol leads to fat storage, inflammation, oxidative stress, suppresses the immune system, and premature aging. Furthermore, it can easily become a vicious cycle because the above mentioned issues are all interrelated so as one symptom becomes aggravated, often many follow.

Thus, endurance activities are not the preferred activity for fatty acid transport or improving your bodies ability to transport. You will want to rely on high intensity weight training or high intensity interval training.

In Part 4, we will look at Oxidation and "Hard to Lose" fat.