How often should you take them?
As mentioned earlier, the speed at which you’re able to digest and process energy gels plays an important roll in how often you want to take them. Because the digestion process will be slowed or halted the further you get into the race, you need to be careful not to overload your stomach. I suggest waiting about 45-60 minutes between gels before taking another one. Most runners should be closer to the 60 minute mark, especially if they have sensitive stomachs.
The second reason to wait 45-60 minutes between taking gels is that you don’t want to speed too much simple sugar into your blood stream at once. Remember, the simple sugars from the energy gels will first be absorbed into your blood stream as glucose. The sugar will stay in the blood stream until absorbed by the working muscles or other organs. If you continue to pump sugar into the blood stream, you’ll suffer the same fate as your children if left alone on Halloween — sick from too much sugar.
The other aspect to keep in mind is that your digestive track is trainable like most every other part of your body. So, if you eat gels in training, particularly if you do it at set intervals that correlate to when you will take them during the race, your body will learn to keep the digestive track running and you will digest the gel more readily. This is why it’s critical you practice your exact fueling strategy as often as possible in training.