Author: Andy Blow
Source: 220 Triathalon magazine (Australia/NZ), Issue 12, pp. 34
Energy bars are designed to provide a concentrated amount of energy, in the form of carbohydrates, to fuel muscles before or during exercise. They generally release energy a little more slowly than carbohydrate gels or drinks as they take longer to break down, so are more suitable for pre-exercise carb loading. Some may contain small amounts of other nutrients, such as protein, or caffeine.
- When you start eating an energy bar your mouth immediately begins to break down the bars simple sugars using salivary amylase (in the same way it does with an energy gel). As you chew it up and swallow the bulk of the bar, it moves into your digestive tract to be broken down further.
- Within your gut, the carbohydrates are broken down into small molecules that can cross the intestinal wall into the bloodstream. This happens more slowly than with a gel or drink because some of the carbohydrates are more complex and require more processing.
- Once in the bloodstream (as glucose), the carbohydrate triggers the release of the hormone insulin, which activates the cells to take up the glucose and either store it as glycogen for use later on or, if you’re training, at the time when it’s consumed.
- Energy bars are a very dense source of carbohydrates and tend to have a long shelf life. They are convenient way of making sure your glycogen stores are topped up before training and competition if you don’t have access to more natural foods.
Andy Blow is a sport scientist and triathlon coach.