Too many first time century riders fail to complete their rides due to poor nutrition both during training and on race day.
Carbohydrates and Cycling
During various strenuous exercise our bodies usually obtain their energy from the body's store energy known as muscle glycogen. This glycogen comes from the carbohydrates we eat which are broken down into simple sugars and stored in our livers.
When we exercise intensely we have only about enough glycogen to keep us going for anything up to an hour and a half. After that the body begins to start burning fat which does not burn as readily. Once your body reaches this stage you may experience severe fatigue, a tired hollow feeling and a desire to stop pedaling. In cycling this phenomenon is known as the bonk.
How to Avoid the Bonk
To help delay the bonk the century cyclist must try to eat while cycling to help the liver produce more glycogen before it runs out.
Eating high carbohydrate foods (such as bagels, jam and peanut butter sandwiches) will help delay the bonk however when riding hard your body will burn up glycogen faster than you can consume carbohydrates and convert them to glycogen. After some time you will find yourself in what is know as a glycogen deficit. Once you are there if you continue to ride you will soon run out of glycogen and hit the imaginary wall.
The trick to not running out of glycogen is to not only eat the right kind of foods on the bike but also to adapt your training to make your body more efficient at burning fat. If you can do this you will not hit the wall.