Yes but Be careful. After root canal treatment your dentist may place a temporary or permanent restoration in the access. If a temporary has been placed, you need to be careful and try not to chew on the tooth, and if you do, make sure it is not a hard substance. The safest thing to do is to stay away from that side if you can, until you get a permanent restoration, or full coverage crown.
Yes. You can usually eat after most dental treatment. But the waiting time varies based on procedure. After a root canal, usually a temporary filling is placed so avoid eating on that side. If you are not sure, just call up your doctor and ask.