A lot of people mention eating Parle-G during and after rides and I wanted to know whether it is the right thing.
The thing with Parle G is that, correct me if I'm wrong, it contains mainly glucose and simple carbohydrates and so has a really high glycaemic index. This means that you get a quick spike of energy that might give you a burst to let you climb a hill, but isn't good for anything longer. Also, if you eat it when you're not exercising, you cause a spike in blood sugar and then a steep drop because of the flood of insulin--so its use as recovery food is questionable as well.
I mentioned peanut butter and (pure fruit, no sugar) jam on wholewheat bread as a food that works for me. The way I understand it is that you get fibre, complex carbs, a bit of fat, a bit of protein and fructose as against glucose--a slow, regular delivery system for energy. This is good during rides as you don't get an energy spike (and slump) and good for recovery as your body can process the carbs slowly and replenish glycogen, rather than flood the body with insulin and have it all put away as fat.
Even energy gels that don't have fibre feature complex sugars to slow the absorption, not glucose. Apparently, the absorption of glucose is almost instantaneous.
My understanding of these systems is based purely on reading about it, so as always, please rush in if you need to correct something.