Buy the little gu container or the one from hammer gel to avoid trash. I eat about every 30 minutes, and drink a bit of water with it. After several hours I am also taking electrolyte pills and heed from hammer as to sustain myself. After 2 hours your body starts to burn protein, so you have to eat. Have a cliff bar in your back pocket and munch on a little bit of that around that time. Avoid doing it before huge climbs.

The gels are meant to sustain you, not give you a big boost. You take them before you are tired, as they won't help you get back up from bonking.

Also never drink gatorade as it has a lot of simple sugar... an endurance athletes worst enemy.

I'm sure the g2o is fine, as it is designed for endurance athletes and not football players who do short bursts of working out, rather than a sustained long workout.