By: Lucho Crisalle, R.D.
As far as carbohydrates are concerned, not only is the quantity of carbohydrates we consume important, but also as important-if not more so than the quantity, is the quality of carbohydrates. This brings us to a guide called the Glycemic Index (GI). Is it a very useful tool, or useless information? The answer to that question is a resounding YES!
Let us first look at the definition of the glycemic index. It is defined as a guide used to indicate how much a food will increase blood glucose levels relative to pure glucose. Pure glucose, by the way has a glycemic index value of 100. A number from 0 to 100 is assigned to a given food to compare how that particular food raises blood glucose levels compared to 50 grams of pure pharmaceutical grade glucose. The lower the number, the less that particular food resembles pure glucose; the higher the number the more that particular food resembles and acts like pure glucose. In practical terms, the glycemic index is in – fluenced by the form (liquid or solid) in which the food is eaten, its fiber content, the presence of protein and fat, food-processing and food-preparation methods as we learned in the Executive Nutrition article posted on our website at www.ExerciseAndNutritionWorks.com
The GI was developed as follows: a group of test subjects had their blood glucose levels measured and a 50g dose of pharmaceutical grade glucose was administered. The blood glucose level changes were graphed and the area below the curve was recorded and labeled Area “A.”
The same group of people then went through a number of tests where 50g of “X” (rice, bread, yams, pasta, oatmeal, oranges, etc) were administered and their blood glucose response graph and areas were recorded and this area was labeled Area “B.”
Here are the problems with these assumptions:
- Nobody eats rice, bread, yams, pasta, oatmeal, oranges, etc in 50g increments.
- Nobody eats rice, bread, yams, pasta, oatmeal, oranges, etc by themselves.
As noted in the Executive Nutrition article, when combined with protein, and/or fat (as well as fiber), gastric emptying time of carbohydrates changes-it increases, or it takes longer for carbohydrates to “empty” or leave the stomach. When gastric emptying time increases, blood glucose levels do not rise as quickly, changing the blood glucose curve used to determine Area “B.” This change in value for area “B” renders the glycemic index useless unless an individual eats carbohydrates alone (without combining them with protein and/or fat), and in fifty gram increments or portions.
The glycemic index is not simply a function of whether the carbohydrate is in a liquid or solid form. An orange has a glycemic index that is almost identical to the value of orange juice. The glycemic index is also not a function of whether the food is a starch (such as pasta) or simple carbohydrate (such as table sugar). For instance, a baked potato has a glycemic index that is close to the glycemic index for glucose.
So, is it a very useful tool or useless information? In reality, it is both. It is a very useful tool in that the latest research shows it to be beneficial to ingest large amounts of pure glucose or any other high glycemic index food 15-20 minutes AFTER a workout. Five hormones are secreted during exercise: growth hormone, epinephrine, norepinephrine, glucagon, and cortisol. These hormones are insulin-blocking hormones-their main job is to make glucose available for exercise by preventing insulin from storing it. If you were to drink a shake or high glucose drink immediately after your workout, these hormones would block insulin secretion and you would not be able to store much of the glucose in your muscle mass as glycogen to replenish what you just used during exercise. By waiting 15 minutes after your workout to drink your high glycemic drink, these hormones “have died out” or decreased in volume and now allow a large insulin secretion to shuttle all that glucose right into your muscle mass to replenish the glycogen you just depleted during your workout. This is the mechanism utilized to also shuttle large amounts of creatine into muscle cells after workouts by combining creatine with a high glycemic food or drink.
The secret to unbelievable growth – The Glycemic Index and Insulin
If you have been following professional body building over the last ten to fifteen years, you have certainly noticed the increase in size, mass, and thickness of the professional competitors. The reason for that added growth is their use of insulin. There really are no new steroids on the market, no new human growth hormone or any of its derivatives, and there definitely are no new “magic supplements” responsible for this new found growth. The same steroids and growth hormone formulations that were around ten years ago are still the same formulations that exist today, and the only new supplements on the market are the prohormones such as androsteindione and androsteinediol which mimic actual steroids but are sold over the counter because they are considered to be “naturally occurring compounds.” In the past, nobody was using insulin, one of the most anabolic hormones in the human body. When used after a workout, (the same fifteen minute rule applies), insulin forces large amounts of glucose (120-140g) and nutrients such as amino acids, etc right into the muscle mass, increasing the cell volume and causing greater muscle gains. There are different ways of using insulin for added growth-none of which are recommended. The use of insulin IS NOT RECOMMENDED because this is a very risky practice and anyone using insulin can die from its use or completely shut down the pancreas and become dependent on insulin for survival for the rest of their lives. Insulin hardens arteries, and little by little may damage and destroy vital organs, making the fewer years left to live not very pleasant, to say the least.
A much better route to achieve very similar results is to use over the counter products such as Metabolic Response Modifiers- CreActiv, which contains 12 g Creatine Monohydrate, 5g L-Glutamine, 2g BCAA blend, 300mg MicroPlex “No Burn” Alphalipoic Acid, 70g Dextrose, 1g L-Taurine, 500mg L-Arginine, 250mg Vitamin C, 21mg Calcium, 100mg Magnesium, 160mg Phosphorus, 122mg Chloride, and 200mg RNA. CreActiv will help your body secrete higher levels of insulin and increase glycogen storage (along with all the other nutrients listed above) to safely achieve very good results without endangering your health.
In taking advantage of the body’s higher affinity and ability to store large amounts of glycogen by using high glycemic index foods after a workout, as well as reaching for that high GI powder or drink to get through the last mile of a marathon, yes, the Glycemic Index is very useful. For the normal person that goes to the gym, works out three times per week, and eats regular meals, the GI is very useless in that this person will never count his or her grams of carbohydrates; much less take into account how their choice compares to pure pharmaceutical glucose.
In theory, it would be optimal to incorporate mostly low GI foods into the diet. High GI foods are preferable when a quick supply of glucose is needed such as after prolonged strenuous exercise, or as noted above, right after strenuous exercise. However, the combining of protein, fat, and carbohydrates with the high glycemic index food would negate the wanted insulin response.
The glycemic index concept has limitations. The values that are available are based on tests using single foods; it is not common practice to eat corn, pasta, rice, etc all by themselves. We tend to combine these things with proteins and fats, which as explained repeatedly in this article, cause gastric emptying time to slow down. Also, the glycemic index is based on equal grams of carbohydrate, not average serving sizes; not many people are aware of what 50 grams of rice, bread, yams, pasta, oatmeal, oranges, etc look like; the few people I have met who are aware of portion size and how many they get per meal per day, happen to not have a weight problem. Coincidence? I think not.
It should go without saying that these recommendations are made to clients who actually work out at high intensity levels. We do not recommend clients who are just beginning their exercise program to follow this practice of consuming high glycemic index foods fifteen minutes after their workouts, or take a supplement such as MRM’s CreActiv.