Ethics: case 1: a vegetarian situation

Self-tutoring about philosophy and ethics: the tutor visits a scenario that might be familiar.

Many of us have faced a situation like this:

You’re a vegetarian who loves meat. For ethical reasons you no longer consume meat.

A friend offers you a roast beef sandwich they don’t want. You decline, citing you’re vegetarian. You are, however, very hungry.

“Well, if you don’t want this roast beef sandwich, I guess I will throw it out. It will perish by the time I get home. What a shame to waste good food.”

Is it unethical to eat the sandwich? On the other hand, is it ethical to let the sandwich go to waste?