The third factor that effects weight is fat metabolism. Reduced fat oxidation levels have shown an effect on obesity and weight gain.
Since we tend to consume more fat than our body needs at any given time, our body stores the extra fat to be used at times of need. The fat stored in the body is broken down through a complex process known as metabolism. Fat metabolism is the chemical process that converts fat molecules into energy. Lipolysis is the enzymic process by which triacylglycerol, stored in cellular lipid droplets, is hydrolytically broken down to generate glycerol and free fatty acids. The free fatty acids can be subsequently used as energy substrates, essential precursors for lipid and membrane synthesis, or mediators in cell signaling processes. The complete oxidation of free fatty acids to generate ATP (Adenosin Triphosphate) occurs in the mitochondria by the processes of β-oxidation.
Fatty acids are transported into the muscle where they are either stored (as IMTAG) or transported into the mitochondrion, which can be referred to as the fat-burning furnace in a person’s body cells (as this is the only place TAG are completely broken down). As the chemical bonds in TAG molecules are broken up in metabolism, they begin to lose electrons (a process called oxidation) and are picked up (a process called reduction) by electron transporters (NADH+H+ and FADH2). The electron transporters take the electrons to the electron transport chain for further oxidation, which leads to a liberation of energy that is used to produce adenosine triphosphate (ATP). Unused energy becomes heat energy to sustain the body’s core temperature. This ATP synthesizing process depends upon a steady supply of oxygen, which is why this process is aptly nicknamed “aerobic metabolism” or “aerobic respiration.”
What factors can affect slow lypolisis?
It seems like some people specially thinner individuals tend to have a higher oxidation rate compare to overweight or obese individuals. The reason behind this is not completely understood, but it could be related to genetics. Some factors that seem to affect fat oxidation are (1):
- Muscle fiber type may vary between lean and obese individuals. There are two types of muscle fibers, slow twitch and fast twitch. Slow twitch muscle fibers are better in aerobic metabolism and hence fat oxidation. Fast twitch muscle fibers do better under anaerobic metabolism, so they oxidize carbohydrates better. Individual with lower rate of slow twitch muscle fiber to fast twitch, will have a lower fat oxidation rate.
- Individuals have different amount of enzyme lipoprotein lipase, which is responsible for use of fat for energy in muscles. This can affect the fat oxidation rate in individuals.
- Obese individuals produce lower amounts of epinephrine, the cathecholamine responsible for release of fat from adipose tissue, or they may be less sensitive to it.
Is it possible to increase fat oxidation, and how?
Luckily, there is a way to change and increase your fat oxidation rate. As you probably have guessed it, exercise can help with improving the fat oxidation rate, but the intensity and duration matters. According to one study:
Fat oxidation rates increase from low to moderate intensity and drops as the intensity becomes high. This study suggests that the maximal amount of fat oxidation is when a trained individual is at intensities between 59%-64% of maximum oxygen consumption (VO2 max) and general population is between 47%-52% of VO2 max.
Mode of training is another factor that influences fat oxidation. For example, higher fat oxidation in running compared to cycling
The diet also affects fat oxidation: if carbohydrate gets consumed in the hours before or during the exercise the rate of fat oxidation will decrease significantly compared to fasting conditions. Also fat oxidation rates have been shown to decrease after ingestion of high fat diet.
If you are trying to burn fat and increase your fat oxidation rate:
You need to know your VO2 max and try to exercise at the intensity that will put you between 47%-52% (for general population) of your VO2max.
Here is how you can measure your VO2 max:
You can have this measured professionally at some medical facilities and training centers. The test typically involves breathing into an oxygen mask while walking on a treadmill at a certain pace for a certain amount of time. However, this test may be too expensive. Because of this, physiologists and sports scientists have devised other formulas you can use to calculate your VO2 max, using factors such as your age, resting heart rate, and maximum heart rate.
Here are two of these alternate formulas for calculating your VO2 max:
Using your resting heart rate and age:
- VO2 max = 15.3 x (MHR/RHR)
- MHR = Maximum heart rate (beats/minute) calculated using age = 208 – (0.7 x age)
- RHR = Resting heart rate (beats/minute) = number of heart beats in 20 seconds x 3
The Rockport Fitness Walking Test (RFWT) using a 1-mile (1.6-kilometer) walk:
- VO2 max = 132.853 – (0.0769 x W) – (0.3877 x A) + (6.315 x G) – (3.2649 x T) – (0.1565 x H)
- W = Weight (in pounds)
- A = Age (in years)
- G = Gender factor, G = 0 for females and G = 1 for males
- T = Time to complete the 1-mile walk (in minutes)
- H = number of heart beats in 10 seconds at the end of the 1-mile walk
Knowing and keeping track of your VO2 Max can be difficult during the exercise, but you can track your heart rate by using a heart rate monitor. To simplify according to American college of sport and medicine, 47% of VO2 max equals to 67% Max heart rate and 52% VO2 max equals to 71% MHR.
Don’t eat foods high in carbohydrate within the hours before you exercise or during the workout.
Stay happy and healthy
Without the fat oxidation process, fat molecules would stay in their larger form. The larger molecules can’t be used as energy by the body, so, they just stack up. They provide some insulation, but that’s about all. So, fat oxidation is extremely important, if we want to function on a daily basis.
How does the magic happen? Well, our bodies are full of hormones and it’s the job of some of those hormones to regulate the triglyceride conversion. It’s a bit like controlling a valve to slowly release air into a tire or balloon. Without that slow release, we’d have far too much energy being released to use at a given time and we’d run out in times of need.