I haven't stopped eating those things completely, but I've really cut down on the amount of flour based products I eat.
I haven't given it up all together, but I've really reduced the amount of breads and noodles I eat.
この場合、次のような言い方ができます。
ーI haven't stopped eating those things completely, but I've really cut down on the amount of flour based products I eat.
「小麦製品を完全に食べるのをやめたわけではないが、食べる量をかなり減らした」
to cut down the amount of ... で「…の量を減らす」
ーI haven't given it up all together, but I've really reduced the amount of bread and noodles I eat.
「全部まとめて絶ったわけではないが、パンや麺類の食べる量をかなり減らした」
to give up で「絶つ・（食べるのを）やめる」
to reduce the amount of ... で「…の量を減らす」
ご参考まで！
カナダ 
