Probably depends on your white bread. My understanding is that any glycemic delta in white bread is primarily a function of the fiber. White bread without fiber is, to a first approximation, sugar.

White bread is just syntactic sugar for simpler sugars, and destructures into them in your gut.

A lot of white bread has actual sugar or high-fructose corn syrup in it as an ingredient. How much of that is to start the yeast and how much is for taste varies by brand.

Whole-grain/white can be misleading as far a sugar goes. I've had whole-grain brands that were so sweet that I couldn't stand to use them for sandwiches.

> White bread has a higher glycemic index than sugar.

Doesn't seem to be so: http://nutritiondata.self.com/topics/glycemic-index

For further reference (as it seems I've been downvoted possibly for my own snark on this one) - since I can no longer edit the original comment, here are some references

This appears to be the one I recall: http://calmerthanyouare.org/2015/03/19/betteridges-law.html

My numbers were off it's actually 46% "non-polar", 20% "yes", 16% "maybe" and, 15% no

https://news.ycombinator.com/item?id=9232419

Additionally there was a publication in a statistical journal which also discussed the "phenomenon" http://link.springer.com/article/10.1007/s11192-016-2030-2 which also found that it wasn't a factual assertion (in academic papers).

Anyways - if the downvote was for something other than my own snark I'd love to hear what it was.

Apologies for coming off as a jerk.