Nutrition Series: Carbohydrate Energy

Nutrition Series: Carbohydrate Energy

Of all three macro-nutrients: carbohydrates, proteins, and fats;

carbohydrates are the most misunderstood, and easily confused.

 

via: Choose my plate

There are many reasons for the confusion, just comparing:

• The Government’s  ChooseMyplate lists: fruits, vegetables, grains, protein, dairy, and oils; to
• Known macro nutrients: Carbohydrates, Proteins and Fats.

What gives? Are the ChooseMyPlate foods, the same as macro nutrients? Yes, they are just categorized differently.

The ChooseMyPlate food table has 6 food categories; while macro nutrients have 3 items to choose from.

Lets get them aligned to better understand where they fall

• Carbohydrates: fruits, vegetables, dairy, and grains
• Proteins: neat foods
• Fats: oils

Lets discuss the basics macro nutrients, not the recommended government eating plan; today I would like to talk about carbohydrates specifically.

Harvard’s School of Public Health describes carbohydrates like this:

“The best sources of carbohydrates—whole grains, vegetables, fruits and beans—promote good health by delivering vitamins, minerals, fiber, and a host of important phytonutrients. Easily digested refined carbohydrates from white bread, white rice and other refined grains, pastries, sugared sodas, and other highly processed foods may contribute to weight gain, interfere with weight loss, and promote diabetes and heart disease. Carbohydrates start to be broken down in your mouth as you chew and by becoming mixed with enzymes called ptyalin that are produced by your saliva glands.  Ptyalin will start to break down the larger starch molecules into smaller molecules.  The carbohydrates will then pass through your esophagus into your stomach at which time they mix with pepsin and hydrochloric acid. The main absorption on nutrients takes place in the small intestine. The pancreas releases amylase which completes the digestion of starches.”

• What happens when carbohydrates molecules get into your small intestine?

Carbohydrate (Mono, Oligo, Poly saccharide) digestion starts in the mouth with a combination of chewing, mixing with saliva, then travel to your stomach to be mix further with hydrochloric acid and pepsin. The body breaks down the carbohydrates into small single molecules (monosaccharides) to be acted on the small intestine. These molecules are absorbed by villi in the small intestine, travel to the liver, needed glucose sent into your bloodstream, while unused glucose is converted or stored as needed.

• How do they become: energy, bodyfat or brain fuel?

Once absorbed about 5 grams, or 20 calories, circulates as glucose, which is used to fuel the brain and organs. Some of the glucose is to be stored as glycogen in the liver and muscle, the balance is stored as fat. The “Bodybuilder’s Nutrition Book” written by Franco Columbo, states that the human body can store only 350 grams of glycogen; one-third in the liver and the remaining in muscle. Any excess glucose that can not be stored would be converted into bodyfat for later use.

Glucose in our bodies does more than fuel our muscles but also is used to support the brain and central nervous system. When there isn’t enough glucose in our blood stream you might notice coordination issues, lack of concentration or an increase in injury might occur; there could be various mood issues. When there isn’t enough glucose in the blood, muscles or liver, the body begins to convert fats and proteins into glucose for fuel. When converting proteins the body releases a lot of fluid, this could cause lowered healing properties, this large release of fluid accounts for the initial weight loss experienced when following a low carbohydrate diet. Another concern, when following a lowered carbohydrate diet, is the additional release of cortisol, which contributes to further break down muscle tissue.

While we sleep our body utilizes the glycogen stored in our liver to fuel body functions like: breathing, the beating of your heart, and the actions of your liver and kidneys.

• During low-level aerobic exercise our body will use a combination of carbohydrate, fat and protein to fuel movement.
• During intense anaerobic exercise it is carbohydrates that fuel our muscles.

The first part of exercise,muscle relies on stored energy in the form of glycogen, which needs to be converted to glucose before providing energy. As activity continues muscle glycogen is reduced, at that point the body takes up the stores of blood sugar (glucose), your blood only contains so much glucose. As the blood sugar (glucose) starts to be depleted the liver releases its stores of glycogen into the blood stream in the form of glucose. Once all the liver glycogen is gone, protein and fats will be converted to glucose to provide fuel and feed muscle tissue.

A sedative person might be able to maintain their stored glycogen for longer periods of time while a physically active person will burn through their glycogen stores very quickly. Once the glycogen stores are gone from your muscle the body has to revert to the less efficient means of energy, utilizing the liver to convert stored glycogen or amino acids from muscle into glucose. This isn’t the best option as it taxes the liver and takes muscle-building amino acids away from the muscle when they are needed most for rebuilding and repair.  Since it can take 24 hours to replenish  muscle glycogen stores , it is recommended to training heavily every other day for maximum results.

These are the two forms of exercise and how they convert carbohydrates for burning energy:

Anaerobic System: (without oxygen) used for quick speed exercises like quick sprints or 100 meter dash for a quick burst of energy ie high energy for short periods of time.  To create or metabolize energy the body doesn’t use oxygen. The only fuel your muscles can use is glucose,which is stored as glycogen in muscles waiting to be used, if there isn’t enough glycogen stores proteins and fats are converted if blood or liver glucose is no longer available. There is a step by step process when glycogen is broken down to glucose to provide energy to the muscles; enzymes cause the glucose to change at each step, this is called glycolysis.  Part of the process releases a by-product is very important as it’s the true source of muscle contracting energy and called ATP or adenosine triphosphate.  Breaking apart the ATP molecule is the source of the energy. Creatine helps recycle the ATP after it’s use to create more energy and use the ATP system more efficiently.

Aerobic System: (with Oxygen) Used to provide energy for prolonged endurance based exercises. Still uses the step by step process to create energy but it does it with oxygen and gives off a lot more ATP (adenosine triphospate) so you can work longer.  While some protein can be a source of aerobic energy the main source is fats and carbohydrates.  Carbohydrates are an easier source than the high density fat stores, which has to go through a process before it can be used as an energy. A very fit person tends to have trained their body to utilize fat stores more efficiently by producing more fat burning enzymes.

I hope you have enjoyed the detail so far, if you have any questions please feel free ask as it helpful to hear your thoughts regarding this post series.