hi, i was wondering if there are any advantages or disadvantages of eating a whole wheat sandwich vs. white flour breads during an Ironman? (and i don’t mean as a spectator 
how long after eating whole wheat does your body begin to use the carbs from it vs. how long does it take with white flour breads?
Go with the white bread. It has less fiber which translates to faster absorption and fewer GI issues.
Hi efesefes, it’s a bit tekky but this page on nutrition might help. It doesn’t answer exactly what you are after but it’s pretty informative. The key too to nutrition is to try it in training. Everyone reacts differently to different foods so just stick with what you are most comfortable. I know for sure that the fibre in whole grain breads would play havoc with my gut but I know that this is not the case for everyone