Endura Sports Energy Gels are a concentrated form of carbohydrates that include "immediate impact carbs" and "slow release carbs" that work together to give you the quick energy hit as well as a longer lasting source of energy. Because they contain no sucrose, they won't give you the "energy spike" and resulting "energy low" that follows when you would normally eat a chocolate bar or sugary snake. Instead, you'll have a consistent level of energy that is more useful for riding and avoiding that

Typically, we find that riders view sports gels as a sugary, sweet burst of energy that is only useful for when you've hit the wall and you need that big dose of carbohydrates to get you through to the end. The harsh reality is, that if you feel like you're about to hit the wall, then you're too late! As the body's energy levels are on a constant decline during excercise, the best thing you can do for your riding is to keep that energy level as constant as possible, and pre-empting that energy low will allow you to keep riding for longer.
If you're feeling a bit low on energy before you've even started your ride, then having a sports energy gel 10 minutes prior to jumping on the bike is the perfect way to get those energy levels up so that you will last longer and feel fresher. 

From Endura:

What is a Sports Gel?
Endura™ Sports Energy Gels are a convenient energy source with energy boosters like caffeine, and a blend of immediate impact and slow release carbohydrates to sustain energy levels. You can store them on you and just take with water as you need. They are an easy way of keeping glycogen levels up and are suitable for taking either during the whole event, or to get you through when you hit the wall.

Do I just eat the gel by itself?
It is best to drink water when you consume gels, to avioid gastric upsets. For each gel consumed, look at drinking around 250-300 mL of water to achieve an isotonic solution for best absorption. Some athletes may find drinking so much water in one hit difficult. If this is the case take the gel over 10–20 minutes and have small sips with every portion, to reach around that 250-300mL total.

Why do these gels taste sweet?
Endura™ Sports Energy Gels are sweetened with specialised branched chain glucose polymers and microcrystalline fructose which provide rapid gastric emptying and absorption.

Where does the energy come from?
Endura™ Sports Energy Gels are a concentrated source of carbohydrates, providing a big boost of energy in a single compact serve. Endura™ Sports Energy Gel contains 26 g of carbohydrates to replenish your glycogen stores and give you the fuel to keep going. So when you need a blast of energy in a convenient, quick and easy form, take an Endura™ Sports Energy Gel!

Directions:

For Best Results, consume one 35 g serve (1 1/3 tablespoons or 26.4 mL) or one sachet:

• Before exercise - 15 minutes prior to exercise.
• During exercise - Every 30 minutes with fluid to prevent glycogen depletion and energy loss.
• After exercise - Directly after exercise to aid recovery.

The Endura Sports Energy Gel features:

• Single serve per 35gm packet
• Concentrated carbohydrate
• Blend of quick release and slow release carbs for maintaining energy levels
• Low GI
• Contains no sucrose or simple sugars