Dextrose

John, 

I’ve been hearing a lot of talk about using dextrose pre/post-workout to get carbs in the system, but I haven’t been able to figure out if it is bullshit or not. I work out in the AM, and it’s tough to crush a few pounds of meat and sweet potatoes before rolling into the office at 9 AM. What is your take on dextrose? If it is a legit way to go? What dosing do you recommend and how does it apply to leaning/bulking? And does it affect your macro kcal shares later in the day? Or should I quit being a pussy and just eat more?

Thanks to PAHQ for all the free info and great programming.

BA

Let’s start by identifying what dextrose is and see how it might fit into the grander scheme of performance nutrition.

Dextrose is the name of a simple sugar chemically identical to glucose (blood sugar) that is made from corn. In many cases dextrose is used in food products as a sweetener, but it also is used extensively for medical purposes. Dextrose dissolves very well in IV solutions, which can be combined with other drugs, or used to increase a person’s blood sugar. Since dextrose is a “simple” sugar, the body can use it rapidly for energy.

Simply, glucose is dextrose and dextrose is glucose.

But what is glucose and why is it important in the body?

All parts of the body, it’s muscles, brain, heart, and liver need energy to complete their given tasks; this energy comes primarily from the food we consume.

The process of digestion starts in the mouth where the chomping of our teeth break down food into small particles, mixing them with saliva and enzymes. After the food is swallowed it mixes with acids and enzymes in the stomach. During this process the carbohydrates, sugars and starches, in the food breaks down into a sugar called glucose.

The small intestines absorb the glucose and release it into the bloodstream. Once it enters the bloodstream, glucose can be used for energy or stored in our liver for later use, thanks to insulin. One of insulin’s primary functions is converting food (glucose) into glycogen. And for those of you that can remember O-Chem from college, glycogen is stored in the liver and muscles and is what we can tap into for energy.

Insulin has other roles outside of glycogen conversion as it also helps our bodies store fat and protein. All cells in the body need fat and protein to function property.

For those that have been following along with Power Athlete Radio and our recent array of guests that have to do with the Ketogenic Diet (Dr. Ken Ford, Dr. Di Pasquale, Robb Wolf, Dr. Perlmutter), you will note that body can convert protein to glucose in a process called gluconeogenesis.

Gluconeogenesis is the production of glucose from protein since the brain, testes, red blood cells and kidneys utilize glucose for ATP production. The brain utilizes large amounts of the daily glucose for sources that are consumed or via gluconeogenesis. However, in addition to glucose, the brain can derive energy from ketone bodies, which are converted to acetyl coenzyme a and pushed into the Krebs cycle.

When fats are absorbed into the small intestines, the glycerol is separated from the fatty acids, and the fatty acids are broken into pieces in the liver known as ketones.

Ketones can be used as a source of energy, like glucose, as they eventually become carbon dioxide and water. The production of ketones by the body is part of a normal process.

What is intriguing is the amount of ketones formed in the liver depends on the amount of glucose and by default glycogen available for use as energy. This inverse ratio translates to fewer ketones in the presence of more glucose. The reason for this is that insulin suppresses the formation of ketones. When glucose is being used for energy, ketones are simply not needed. On the other hand, in the absence of sufficient insulin, the body metabolizes stored fats to produce the energy the brain, RBC, muscles and organs need. One point to note, the brain can only power 70% of its action on ketones; the 30% deficit is backfilled by glucose. The glucose, in a no/low carb environment like Ketosis, is derived from gluconeogenesis.

Now that we have identified what dextrose is and how the body uses it, lets examine where it fits into our training and nutrition protocols.

Dextrose is a simple sugar that is very easily converted to energy in the body. Knowing this, I recommend using dextrose as a source of carbohydrates in an intra-workout shake. I have found that offering CHO and PRO in liquid form during a workout window will result in better performance – shocker.

What that said, if you were following a Ketogenic approach, consuming dextrose in before, during or after workout would disrupt the product of ketones by raising insulin levels. Thus negating the effects of Ketosis and being counterproductive.

If you were to consume 75 grams of dextrose in your intra-workout shake I would definitely add those to my daily caloric intake.

Whether or not you are a pussy and should eat more depends on what your goals are. If you are following the Bulking Protocol, then yes, you need to man up and eat more. If you are following the Leaning Protocol, track your macros and total daily caloric load to reach your goals of a leaner you.