FOR lunch=)

"I ate chicken, rice and pasta FOR my lunch" would be grammatically correct. However, it is far more common for native speakers to use the verb "to have" (instead of the verb "to eat") and it is also far more common to simply say "lunch" (instead of saying "my lunch"). Thus, your sentence would be: "I had chicken, rice and pasta for lunch". More examples: We usually ask "what are you HAVING for lunch?" (not "what are you EATING for YOUR lunch?") We usually reply "I am HAVING chicken for lunch" (not "I am EATING chicken for MY lunch") We usually ask "what did you HAVE for lunch?" (not "what did you EAT for YOUR lunch?") We usually reply "I HAD chicken for lunch" (not "I ATE chicken for MY lunch"). Note: this same rule applies to other meals (breakfast, dinner, tea, supper). We would ask "what did you HAVE for breakfast?" (not "what did you EAT for YOUR breakfast?") We would say "I HAD sausages for dinner" (not "I ATE sausages for MY dinner") etc etc