Energy gels offer a concentrated source of energy making it easier to replace lost energy stores whilst training and racing. Bollox energy gel contains maltodextrin which directly provides glucose to your blood stream as well as fructose which has a longer absorption time kicking in a little later.
Maltodextrin, unlike fructose, has a high glycemic index which ranges from 105 - 136 on the glycemic index chart while fructose has a much lower glycemic index of 19. A high glycemic index means that it goes through the digestive system and into the bloodstream very quickly. This can be helpful to sustain you during an intense workout.
In theory, energy gels should be taken during exercise. They work by immediately raising your blood sugar level with fast released carbs followed by slow-release sugars for prolonged energy supply. While exercising, the body will be using all the carbohydrates that are released. However, when taking a gel while not exercising, the body will convert the gel’s carbs into long term stores (glycogen), hence gradually lowering blood sugar levels again. Thus, if you take energy gels 1 or 2 hours before a race, the actual benefit will be gone at the race start.
So if taking gels 1-2 hours before the race will not help you much, you may ask why it is beneficial to take an energy gel 15-20 minutes before race start?
1) It’s all about timing
Since it takes some time for the carbs to enter your blood stream it’s best to take a gel 15-20min before race start. By doing so the sugars start hitting your blood stream when you need them, right at the race start. The carbs in the gel will give you that relatively quick burst of energy which your body will use as soon as you start exercising.
2) Psychological effect
There is another benefit, even before you’ve actually digested the gel. It’s the physiological energy boost of consuming gels even before gaining the more substantial benefits once the sugars have been processed through your digestive system. This particular benefit has been intriguing numerous researchers.
There are severals studies published where athletes take a carbohydrate solution, swish it around in their mouth and then spit it out, but they still receive an energy boost . This tells us that the performance benefits from consuming energy gels aren't necessarily all about utilizing its sugars as an energy source, but also be about sensing that something sweet is coming.
It seems that this occurs because there are many receptors in the mouth that link directly back to the brain. On detecting carbohydrates, neural signals are released that tell your body it's receiving some nutrients, and allows you to push harder in the short term. So after taking the gel you instantaneously feel like you have more energy, even though it takes a lot more time for your body to absorb the sugars and get them wherever they are needed. And, what is a better moment to get such an energy rush than at race start?
3) Concentrated sports drink
As stated, gels contain mainly sugars and maltodextrins, which make them similar to sports drinks without the water. In order to consume 100 Kcal of energy in the form of a sports drink you will need to ingest 400-500ml of liquid. While that may be useful during hot weather, it may also mean an unwanted sanitary stop. Energy gel has the advantage that it can be ingested with only a few sips of water hence preventing an unnecessary bio break.