Am I allowed to eat anything before my colonoscopy?

No. No- for 2 reasons-1/ it can make visualization more difficult, 2/ you will be sedated, and do not want to run the risk of aspirating food into your lungs.
Depends. Typically the day prior to colonoscopy your diet is limitted to clear liquids and some time during the day you will take a laxative to clear out the colon. Usually, for morning procedures we ask that you have nothing to eat or drink after midnight before the procedure due to the sedation and risk of aspiration of stomach contents. Check with your endoscopist for specifics.