With the carbs it is the amount of processing that makes a big difference as well, white bread, white rice and 2 minute noodles are digested very quickly and spike the blood sugars whereas whole grain bread, brown rice and wholemeal pasta are digested more slowly (low GI) so are less stressful on the system. Generally low GI foods leave you feeling full for longer so you are less likely to crave for another snack as well. If in doubt just follow my late mothers policy, less processing is best.