A common sight in many gyms are people walking around with water bottles that clearly aren't water. They tend to sip from these bottles throughout the workout. The contents of these bottles differ and can vary from amino acid concoctions to nutrient drinks ostensibly promoted to increase anabolic effects during training. But far and away the most common primary ingredient in these intra-workout drinks is carbohydrates. This makes sense and it doesn't make sense. Sounds paradoxical? Let me explain. Carbohydrates are by far the most effective energy-producing nutrient. Although fat is the densest source of calories at 9 per gram compared to the 4 per grams found in carbohydrates and protein, of the three nutrients, carbohydrates are the easiest for the body to convert into readily available energy. Carbs digest readily, although this can vary depending on the structure of the carb. The glycemic index is a measure of how rapidly various types of carbohydrate foods enter the blood. Some types of carbs enter the blood much more rapidly than others, and because of this are assigned a higher glycemic index (GI) number. In the past, it was thought that all carbohydrates could be divided into two primary categories: simple and complex. However, with the advent of the GI, it was apparent that the picture was not that simple.
Foods that were long considered complex carbohydrates in the assumption that they took a long time to digest, turned out to be digested far more rapidly than previously believed. One example of this is potatoes. Potatoes were considered a high starch food that presented a picture of being a complex carbohydrate. But according to the glycemic index, potatoes, when consumed alone without butter or anything else added, are rapidly absorbed into the body. Thus, potatoes have a higher GI number than even white sugar. It turns out that the starch found in potatoes is rapidly digested, leading to a rapid increase in blood glucose levels. On the other hand, sucrose or table sugar is classified as a disaccharide, consisting of two simple sugars, fructose, and glucose, bonded together. But that bonding of sucrose means that it must be degraded by specific enzymes in the gut and this takes a bit longer to occur compared to the rapid digestion of starch found in potatoes. Even here, however, results can vary since while white potatoes can have a GI number in the 90s (it goes up to 100), some types of potatoes, such as sweet potatoes, show a GI in the 40s. What that means is that sweet potatos are absorbed slower than other types of potatoes in the body, and also provoke less of an insulin release. That is the problem with higher GI carbs. The faster they are absorbed, the greater the release of insulin.
Insulin is a hormone produced in the beta cells of the pancreas that has numerous roles in the body. The most familiar . . .