How the Body Produces Energy?

Hello everyone. Thank you for visiting my blog and welcome. If you are a returning to SSP then welcome back. In this blog, I am going to discuss the energy systems of the body. It is going to be a little in depth at times in order to have all this make sense. So with that said, let’s begin.

The three main ways that the body utilizes energy are through the Adenosine Triphosphate Phosphocreatine (ATP-PC) system, anaerobic metabolism (without oxygen) system, and the aerobic metabolism (with oxygen) system. The body does not operate one at a time, but fluctuates between them all depending on the demands placed on it.

Chemical reactions of the body (metabolism) happen in two forms. The first is called catabolism or the breaking down of nutrients into usable energy (glucose). The second is anabolism or the building up to create. This occurs when the body is repairing damaged, old or dead cells etc. Food is catabolized into essential nutrients for energy and maintenance. There are six nutrients which are divided into macronutrients and micronutrients. The macronutrients are carbohydrates, proteins, lipids (fats), and water. The micronutrients are vitamins and minerals. They work together to provide renewable energy and continual repair.  

ATP

A major source of energy comes from carbohydrates. Utilization of carbs for energy is the most efficient method of energy metabolism, and they are vital to the healthy function of the brain and nervous systems. Carbs are broken down into glucose, fructose, and galactose. Glucose is the form of sugar we need to create a power house molecule called adenosine triphosphate (ATP is a high energy molecule that stores energy in the form of chemical bonds and supports muscle contractions by changing the chemical energy into mechanical energy during exercise). The liver uses glycogen phosphorylase to convert fructose and galactose into glucose. The glucose can then be used immediately for energy or stored in the muscles and liver as glycogen to be used later (like filling up the fuel tank in your car).

The Glycolytic (Anaerobic) system

The glycolytic system involves the anaerobic breakdown of carbohydrates to produce energy (glucose/glycogen). This process does not breakdown fats and proteins. The substrate (glucose or glycogen) must come from the blood or muscle stores.

The metabolizing of one glucose molecule yields two ATP’s (the energy molecule) without the presence of oxygen. Glycogen yields three ATP’s when metabolized. The ATP is catalyzed by the enzyme ATP-ase to create adenosine coupled with two phosphates (ADP) plus one inorganic phosphate (Pi) and 7 Kcals of energy. It is this release of energy that provides work potential. ATP is stored in the muscles for immediate use; however, it is stored in very small amounts. This limits the work potential of ATP to less than ten second and requires the body to produce a greater number of ATP’s to continue working. It’s like driving your car with the fuel light on. You are moving now, but if you don’t refuel soon you’re going to come to a halt.

Kinase is used to change ADP back to ATP

Enter creatine phosphate (PC) to save the day (I don’t think it wears red and blue tights though). ADP is metabolized into ATP with the use of the enzyme kinase. When PC is in the presence of ADP, kinase is used to bind them together creating a usable ATP molecule.  The creatine phosphate cycle is the quickest process to produce usable energy, but the yield is low. The PC system provides about 10 to 30 seconds of energy and is the primary energy system for high intensity short duration activity like power/strength training or sprinting. The PC system also provides energy at the beginning of all stages and types of exercise. It’s the “first gear” of energy production.  Fatigue is associated with a depletion of PC.

Anaerobic metabolism will provide energy longer than the ATP-PC system alone, but it is limited to about 30 seconds to 2 minutes and is the energy system used the most.  Lactic acid is the byproduct of anaerobic metabolism. We will not discuss the role of lactic acid in energy production at this time.

Oxidative (Aerobic) system

The oxidative system uses oxygen to metabolize carbohydrates and other carbon containing structures (fats and Proteins). This process is very slow but can yield 36-38 ATP’s per cycle. The oxidative system is the primary energy producer in endurance related exercise. Because the oxygen is used to produce energy, there is virtually no limit to the duration of energy production at lower intensity exercise.

One final note, the intensity of the exercise plays a large role in determining the primary energy system. Understanding how your body produces energy will aid you in reaching your next level of performance. This was down and dirty super abbreviated crash course in bioenergetics.  In the future, I may refer to different energy systems being used during exercise, and I hope this helps you follow along.

-Reuben

References

Van, De Graaff, Kent., R. Rhees, Sidney Palmer, R. Ward. Rhees, and Sidney L. Palmer. "Metabolism, Nutrition, and Temperature Regulation." Schaum's Outline of Human Anatomy and Physiology, Third Edition. N.p.: McGraw-Hill Companies, The, 2009. 337-46. Print.

"Exercise Metabolism and Bioenergetics." Nasm Essentials of Personal Fitness Training. [S.l.]: National Academy of Sports Medicine, 2014. 63-74. Print.

"Exercise Physiology." ACSM's Resources for the Personal Trainer. Philadelphia, PA: Lippincott Williams & Wilkins, 2009. 135-39. Print.

Chandler, T. Jeff., and Lee E. Brown. Conditioning for Strength and Human Performance. Philadelphia: Wolters Kluwer/Lippincott Williams & Wilkins Health, 2013. 3-19. Print.

Weight Loss Simplified

I was reading a post from one of my favorite Facebook pages called Ripped Goddess. She asks if her readers find it easier to lose weight or gain muscle. This is an intriguing question because it is multifaceted. Most of you may already know that there is no “cookie-cutter” method to lose weight or gain lean muscle. However, there is a general rule to the process. For this argument, I will address fat loss first because it is the most common goal.

You can raise your chance of success by planing you meals ahead

Before anybody can begin an actual weight loss program, the number of calories consumed daily must be known. The easiest way to get a handle on how many calories you consume daily is by starting a food journal. This can be as simple as writing down everything you eat in a notebook, to using a phone/computer app to record your meals. One of my favorites is “My Fitness Pal”. It helps you establish your target weight and daily calorie goals as well as breaking down your food entries into macro and micro nutrient content. Next is to record your meals for seven days. So if you ate 3000 calories per day for seven days your weekly consumption will be 21000 calories. The next step is to reduce those calories. We are not going to do anything stupid like starvation, we are just going to reduce daily calories by 500. That could be as simple as cutting out that quarter pounder with cheese (520 calories). Just by doing that you change your weekly consumption to 17500. That would be a reduction of >3500 a week. That is fantastic for several reasons.

The first reason is that you haven’t changed anything else in your lifestyle. You can do everything else same as before. Second, one pound of fat is equal to 3500 calories. So by reducing 3500 calories a week you will lose one pound and never set foot in a gym. Third, by increasing your activity level in conjunction with a diet change you will lose even more (be forewarned, for this you may actually have to sweat).

The next step (without going all fitness nerd on you) is to figure out how many carbohydrates, proteins, and fats you need to consume. There are many apps/programs that will calculate this for you already, but it isn’t as difficult as you may think. Ball park numbers are 45/35/20 of carbs/proteins/fats respectively. Using the daily consumption we established earlier, we would break down 2500 calories (remember 3000-500=2500) into 1125 calories from carbs, 875 calories from protein, and 500 calories from good fats. I bet your saying “how the heck am I supposed to know how many calories of carbs/proteins/fats are in my meals?” HA! HA! Let the learning continue!

A little discretion goes a long way toward your weight loss goals

We are going to take the calories needed per macronutrient and divide them by the calories per gram. It is widely accepted that there are four calories per gram of carbohydrates and proteins and nine calories per gram of fat. If we take the figures from earlier we discover we should be consuming 281.25 g of carbs (1125/4=281.25), 218.75 g protein, and 55.5 g of fats (personally, I would not round the numbers at this point, you will see why in a minute).

The final step is to break these values down per meal. I suggest eating more than three times a day. The more often you eat, the longer you metabolism is working to digest and utilize the food. Another reason to eat more often is to reduce the number of calories per meal. It is easier for most of us to eat six small 300 calorie meals rather than three large 600 calorie meals. Ideally we would take the number of grams per nutrient divided by the number of daily meals. This would give us 46.9 g carbs (281.25/6=46.9) per meal, 36.5 g protein per meal, and 9.3 g fat per meal. This is where I would round carbs and protein up, and fat down giving me carbs 47g, protein 37g, and fats 9 g.

So, now we can ball park our progress at a glance by knowing what we require per meal to begin weight loss. This will also help your body function properly by providing the proper amount of macronutrients for work (barring any medical anomalies).

I hope this helps you understand why knowing your daily calorie consumption is the foundation to obtaining your weight loss goals. I admit I made this very simple to comprehend and without scrambling your brain with technical jargon. If you have any questions feel free to ask.

I hope everyone has a blessed day.