Muscle Fuel

It's easy to think of our muscles as gas guzzling engines. The more efficient these engines become, the more gas (or calories, in our muscle's case) they burn.

Our muscles form a vast network of independent cells that work in unison to move our skeletons.For our individual muscle cells to work they must be constantly supplied with an energy source. Our body's preferred source for this energy comes from carbohydrates.The second runner up is proteins, and finally fats.

When oxygen combines with carbohydrates in our muscles, they create the energy source scientists call Adenosine Triphosphate or ATP. Our muscle cells store small amounts of ATP to use during activity. That small amount of ATP available is usually exhausted within the first 3-15 seconds of intense exercise. Our muscle cells then create ATP through one of three biochemical cycles.

The Phosphagen cycle is the primary pathway our muscle cells use to replenish ATP stores. The cells use a compound called Creatine Phosphate (CP) to create ATP, but even this energy supply runs out shortly after exercise begins.

Our muscle cells also use the Gylcolytic cycle to convert the glucose they store into energy. The supply of glucose comes from carbohydrates we've digested.Ý It also comes from stored glycogen found in muscle and liver tissue. Fat stores can also provide an alternate source of glycogen. Glycogen is the body's preferred way of storing carbohydrates for quick access. Before it can be used as an energy source, our bodies must convert glycogen back into glucose. The glucose is then converted into ATP with the help of oxygen. In the absence of oxygen, our bodies create Lactic Acid instead. Lactic Acid causes a burning sensation in your muscles, along with fatigue. Once you replenish your oxygen supply, the Lactic Acid quickly exists.

The third cycle is called the Oxidative. This pathway is most important to endurance athletes because it produces a prolonged energy source.

When the body has exhausted the supplies of ATP it can produce through these three cycles, it resorts to using Branched Chain Amino Acids (BCAA's) to create ATP. BCAA's, which account for 1/3 of all amino acids, are most plentiful in muscle tissue. Leucine and Alanine are two of the 21 amino acids that make up our muscle protein. When necessary, our bodies scavenge these two BCAA's from our muscles and turn them into ATP, ultimately resulting in muscle loss.

This biochemical process is complicated and is not something the body can do easily.

So what does all this science talk translate into for bodybuilders? It means that when we train our bodies need enough calories to function without burning muscle. This can sometimes be a difficult task, particularly when dieting down for a contest. I can't stress enough how important it is to eat protein before and after a workout to prevent muscle
loss. I fill my water bottle with water, protein powder, creatine and Gatorade and drink it while I'm working out. This way I keep my energy levels high, increasing my workout intensity, and I don't have to worry about my body scavenging amino acids from my muscles.

So what about that fat we are all trying so hard to get rid of? From an evolutionary standpoint, our bodies have learned to store energy in the form of fat. Our bodies love to store fat and have an unlimited capability to do so. Unfortunately, it is easier to store fat than it is to burn it away. Our body's fat stores are its emergency energy source for situations like famine and drought. Since this is not a likely scenario for most of us, it is sometime difficult to tap into those fat stores.

Over the years I've tried many different routes to lose fat. The simplest and most efficient way is to simply stay lean in the off-season. I used to pack on 30-40 lbs in the off-season, which meant extra cardio and crash diets leading up to contest time. Because I had to restrict my calorie intake so drastically to lose fat, I lost muscle mass and my workouts suffered. At contest time, I usually ended up totally depleted and not
any bigger than the previous year. I now keep myself at 4-5 % body fat in the off-season without compromising any strength and I am able to train with 110% intensity right up to the day of the show.

[THE CARBOHYDRATE CATCH]

You can find carbohydrates in almost everything we eat -- whole grains, fruits, vegetables and dairy products. All carbohydrates are essentially sugars, but they are not all alike. There are more than 200 forms of natural sugars, and all are different in their chemical make-up and the way our bodies use them.

On a molecular scale all carbohydrates contain carbon, hydrogen and oxygen, and all have what chemists call a 5 carbon ring. Sugars with single one of these carbon rings are called monosaccharides, those with two carbon rings disaccharides, and those with multiple carbon rings are polysaccharides.

The simplest of all carbohydrates is the monosaccharide glucose. Other monosaccharides include fructose and galactose. Common disaccharides include maltose, sucrose, and lactose. Polysaccharides come from glycogen found in animals and starch, long chains of glucose molecules found in plants. When we eat starch, such as potatoes and rice, our bodies can easily break the bonds that link these glucose molecule chins and use the glucose as an immediate energy source. Our bodies make use of glucose on a cellular scale to fuel muscles and for a variety of other cellular
functions.

Not all carbohydrates are created equal. When we eat any form of carbohydrate our bodies convert the sugar into glucose through a complex series of biochemical steps. The physical and chemical properties of each of these sugars effects the way this happens. To help keep track of this, chemists created the glycemic index. The glycemic index ranks the sugars on a scale of 1 to 100 depending on how quickly our bodies break them down. The speed of this transformation affects the amount of insulin released into our blood streams. Insulin, a hormone released by the pancreas,
essentially provides a pathway for sugar to be taken in by our bodies, mostly by our liver and muscle cells. Once there, the glucose is stored as glycogen to fill energy needs. Any excess glucose eventually turns into fat. If you eat a carbohydrate that is low on the glycemic index such as brown rice, your body will have a lower concentration of glucose in the blood over time and your insulin levels will be better controlled.

In today's world of weight loss products many foods are labeled as sugar-free. If you look closely at the ingredients on the label, however, you can often find "sugar alcohols" under the carbohydrate listing. These are not actually alcohols, but very complex sugars that our bodies can barely absorb. They commonly come from plant and berry products that are altered in the laboratory. Some examples are mannitol, sorbitol, xylitol, and isomalt. When sugar alcohols are absorbed into the bloodstream, they produce little or no insulin. Although these sugars are able to sweeten many foods without contributing to calorie counts they also have a tendency to cause bloating and diarrhea because your intestines can't properly absorb them. All those free low carbohydrate protein bars you get at the shows most likely have these sugar alcohols in them. I've eaten them during the morning show and become bloated by the afternoon. Bodybuilders beware!

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