I saw a YouTube video that talked about how traditional foods like fish and vegetables that Japanese used to eat suited their bodies better, but there have been so many different western foods introduced to Japanese culture over the last several decades.
この場合、次のような言い方ができますよ。
ーI saw a YouTube video that talked about how traditional foods like fish and vegetables that Japanese used to eat suited their bodies better, but there have been so many different western foods introduced to Japanese culture over the last several decades.
「魚や野菜など日本人が従来食べていたものがどんなに体にあっているか、しかしここ数十年で多くの洋食が日本に入ってきているというYouYubeの動画を見ました」
traditional foods で「伝統的な食べ物・従来の食べ物」
to be introduced「導入される」
ご参考まで！
カナダ 
