This construction is unnatural. It would sound natural to say, "Eating in the laboratory is forbidden." You can also say, "It is forbidden to eat in the laboratory."
Есть = to eat.
Eating = ем, ешь, ест, едим, едят. Also a noun, the act of eating, that's why it can be the subject at the beginning of the sentence "Eating is forbidden."
Word order in English sentences is much more strict than in Russian .
"You cannot eat..." is not wrong, but this Russian sentence would be written on a sign in the library. Your translation would not be on a sign. It is conversational. It should probably be accepted. "One cannot eat..." is strange though. It sounds like people have a medical problem with eating. Maybe "one may not eat..." would be better.