This build-up you speak of, how does it look like precisely? Is it white powdery/chalk-like mass? Does it occasionally burn (especially when it's near the "hole")? If you pull back your foreskin, does it have traces beyond the "pullback borders"? Does it have a foul smell?
If the answer to these questions is ‘yes’, then we might have the same thing. I believe it has nothing to do with sugar (I'm not a diabetic btw). I believe it's a mass of dead oil-based cells (that's why water isn't as effective).
You should try using baby soap (remember, a PH neutral soap, otherwise you’ll hurt the tissue – and you wouldn’t want that, would you). It should clean it off, although they will come back in a few days. Idk why, but they just do.
Have you been neglecting personal hygiene lately? That could cause their appearance. Pretty much like a cold, it’ll occasionally come and go. It’s not something I would worry about.
Sorry for improper use of terms. I don't really know the exact medical phrases, so I had to use the 'vulgar' ones. Hope it doesn't mind though, and I believe it's pretty easy to understand what I'm saying.
I'll try to help you out even if none of the things above fit, but if all else fails, see a urologist (unless the doctors are total dbs where you live too).