Sugar be bad.
There. Corrected. For the non-English speakers.
English is a complex and confusing language. Easy for even native speakers to get confused once in a while.
I was being informal above, using 'sugar is bad.' Sugar be bad is more grammatically correct and formal. Sometimes you hear this formal nature in urban areas or in the southern portion of the United States. Children also have a natural grasp of it, but it gets lost as they grow up and get corrupted in the word. The short reasoning for the use of be vs. is -- Bees buzz. Bees tend honey which is sugar. Therefore, be. It's hard to argue with logic like that. If it doesn't make sense, don't worry. Just stick with is. It's idiomatic. Hope that helps.
I won't even go into why it's bad instead of well. Sugar is inherently evil in this sentence, actually representing, incarnating evilnessness.