Assuming you take a 100 cal gel and are on a run where you burn more than 100 cal, is there any adverse nutritional effect to taking Gu gels? My instinct tells me "it gives you the energy you need, but eating something that's basically candy is never good for you", but what I'm wondering is:
1) Is the sugar in candy unhealthy only if you eat it without burning it off?
2) Since Gu gels are primarily carbs, whereas something like ice cream also contains fat, are you more easily able to burn off the whole gel whereas if you ate ice cream the fat might stay in your system?
3) Are there other food additives (artificial flavors etc) in gels that you don't burn off, and that stay in your system and harm you?