On fast days, Catholics may eat one full meal and two smaller meals that, put together, would not add up to the full meal. That is the maximum amount we may consume. You may eat less if you wish, but it’s not required.
Since the two days each year on which we are obligated to fast are also abstinence days, none of these meals may include meat (chicken, pork, beef, lamb, etc.)
I assume you are not Eastern Catholic. If you are, the rules that apply to you may vary.
