My good friend and I are summer enthusiasts and we spend every breathing minute of it outside in the sun (unless we're working ). We do a lot of biking, blading, soccer etc. At one point my friend was always complaining about how tired he was after each activity, he'd say that he didn't have any energy left and would feel like he wanted to go to sleep. He drank about 3-4 cans of pop (coke) a day (not overly drastic).
One day I took a few friends out biking on a trail, it wasn't a very long ride, maybe a few miles of intense ups and downs, but in the end they all came out panting, especially my buddy, I was as energetic as ever. Then we got drunk one night (haha), and he happened to be drinking rum and coke, later during the night he couldn't sleep at all, and the next day he decided that he wouldn't drink coke ever again. Thus far, he hasn't, but what's changed is that he has more energy than me, we'll go out for a 30-40 k bike and afterwards he'd want to go roller blading for another 10, while I'd be fairly tired. Basically as soon as he stopped drinking coke he's been feeling more energetic than ever, more energetic than me in fact. His muscles are performing better, and he has more energy throughout the day, he even looks "fresher".
I think it may have been the caffeine that was doing this (although it's actually supposed to increase muscular endurance -read articles about it), it may have been the sugar content giving him highs and lows, or maybe the lack of coke increased his water consumption, but I am simply amazed at the change which occurred so suddenly. Personally i never have soft drinks unless I'm having some fast food (which I rarely do), too much sugar and health risks. Anyways, I thought I'd share this with all you people, some of you may find it interesting. Happing Pedaling.