"Es ist kein Zucker da."
What's wrong with 'There is to be no sugar' and what would the translation of that be? Duo does gives 'ist...da' as meaning 'to be'. So frustrating some times.
"ist...da": a better translation would be "to be there/here" like "Der Weihnachtsmann ist da!" (Santa Claus is here), "Ist da jemand?" (Is somebody there?)
"There is to be no sugar" makes it sound like you are a king with an aversion to sugar, like you are making a rule to forbid sugar. The best translation for that is "Es darf kein Zucker da sein!" or "Es darf keinen Zucker geben!"