The act of eating can be very telling in a dream, or it can simply stand for basic survival.
Did you acquire your food in the normal manner or in some unusual way? Is the food recognizable to you or is it something you've never had?
Watching others eat may reflect a deficit concerning your own material or emotional needs. This may be from a pity-party perspective or from the view that others are gluttonous. In this case, it is worth it to ask who you are watching eat and why haven't they invited you to join.
What style of eating is prevalent in the dream? Grotesque gorging and gluttony may indicate excess in your life or the relationship you share with other eaters.
Is the food consumed with great ritual and sacred decorum? This may indicate a sense of providence or divine guidance in an aspect of life.