YOU SAID:

The cat tried to eat the mat but the mat was too fat

INTO JAPANESE

猫はマットを食べようとしましたが、マットが太すぎました

BACK INTO ENGLISH

The cat tried to eat the mat, but the mat was too thick

INTO JAPANESE

猫はマットを食べようとしましたが、マットが厚すぎました

BACK INTO ENGLISH

The cat tried to eat the mat, but the mat was too thick