some nice answers here wrt post-workout meals!
there is nothing wrong with carbs…but not all carbs are made equal! junk is junk and eventually that catches up with you. it's ok in a pinch once in awhile but as sarensho mentioned, going from super low to super high blood sugar can lead to diabetes by messing with your hormone/insulin system. the impact of a complex carb vs a single sugar is significant.
i study nutrition and am an avid runner/cycler. my approach is usually:
night before: meal based on complex carbs (yams, whole grains and starchy and non-starchy veg) with easily digest lean protein (fish or small amount lean chicken/beef cuts)
morning of (mix complex and simple carbs, protein and fats): smoothie with lots of frozen berries, banana, avocado, whey protein, hemp seeds, turmeric, ginger etc
during ride/run: simpler carbs - figs, dates, other dried fruit and if it's a long day nuts, lara bars or a few chews.
1-2h after: mix protein and simple carbs
night meal: protein and complex carbs and some good fats - probably also a treat! this is the time to eat it!
i've found as my training level increases i crave sugars more and if i don't eat the good ones i resort to junk! so i up my fruit snacks during the week and complex carbs in general.