toasting bread

hey bros, this may be a silly ?? but last night while eatin my tuna i got to thinking of back in the day when we tried to figure out the cals of food in class with use of bunsen burners. we would burn the food untill it ashed up, then figure out the cals it took to burn the food.
so, i pose this.. would toasting bread, wheat or what ever, have a significant impact on the nutrients of the bread.,..are there any pros/cons of doing this?

thanks inadvance for any feed back.

no one has thoughts about this? ahhh maybe it was a silly damn question anyways