In order to avoid having to waste food, for me, I serve only as much as I can eat.
I don't want to leave any food on my plate, so I only take as much as I know that I can eat.
ご質問ありがとうございます。
①
"In order to avoid having to waste food"＝「食べ物を無駄にしなくて済むように」
"for me, I serve only as much as I can eat."＝「私が食べられる分しか自分によそいません。」
②
"I don't want to leave any food on my plate"＝「自分のお皿に食べ物を残したくないので」
"so I only take as much as I know that I can eat."＝「自分が食べられる分しか取りません。」
ご参考に！
アメリカ合衆国 
