Ashi ga Hayai (足が早い - Spoil Rapidly)

I bought a Costco's new cake, "Strawberry Trifle" yesterday.

Since cakes are "ashi ga hayai" (足が早い), I have to eat all of them by tomorrow.

Here, the literal meaning of "ashi ga hayai" is that something's legs are quick, and it means that food or something is spoil quickly.

"Ashi" (legs/feet) could represent changes in movements or states of things, and perishable things change quickly (hayai - 早い), so they have come to be called "ashi ga hayai."

Also, based on the same etymology, "ashi ga hayai" can mean that a product or something sells fairly well.

足が早い

私は昨日、コストコの新作ケーキ「ストロベリーストライフ」を購入しました。

ケーキは「足が早い」ので、今日か明日までに食べきらないといけません。

ここで「足が早い」は、食品などが腐りやすいことを意味します。

「足」はものごとの移動や様子の変化を表すことがあることから、「腐りやすいもの」は「足が早い」と言われるようになったとされています。

また、同様の語源から、「足が早い」は「商品の売れ行きが良い」ということを表すこともあります。

• I bought a Costco's new cake, "Strawberry Trifle" yesterday.
• I bought one of Costco's new "Strawberry Trifle" cakes yesterday.

• Since cakes are "ashi ga hayai" (足が早い), I have to eat all of them by tomorrow.
• This sentence is perfect! No correction needed!

• Here, the literal meaning of "ashi ga hayai" is that something's legs are quick, and it means that food or something is spoil quickly.
• Here, the literal meaning of "ashi ga hayai" is that something's legs are quick, and it means that food or something spoils quickly.

• "Ashi" (legs/feet) could represent changes in movements or states of things, and perishable things change quickly (hayai - 早い), so they have come to be called "ashi ga hayai."
• This sentence is perfect! No correction needed!

• Also, based on the same etymology, "ashi ga hayai" can mean that a product or something sells fairly well.
• This sentence is perfect! No correction needed!

"Product or something"
"Food or something"

This is not natural English although it does not break any grammar rules. You might consider using "et cetera/etc." here, although overuse becomes awkward very quickly.

• Ashi ga Hayai (足が早い - Spoil Rapidly)
• Ashi ga Hayai (足が早い - Spoils Rapidly)

• I bought a Costco's new cake, "Strawberry Trifle" yesterday.
• I bought a Costco's new cake, "Strawberry Trifle" yesterday.

• Since cakes are "ashi ga hayai" (足が早い), I have to eat all of them by tomorrow.
• Since cakes are "ashi ga hayai" (足が早い), I have to eat all of ithem by tomorrow.

  Since you mentioned only - a cake

• Here, the literal meaning of "ashi ga hayai" is that something's legs are quick, and it means that food or something is spoil quickly.
• Here, the literal meaning of "ashi ga hayai" is that something's legs are quick, and it means that food or something is spoils quickly.

• "Ashi" (legs/feet) could represent changes in movements or states of things, and perishable things change quickly (hayai - 早い), so they have come to be called "ashi ga hayai."
• This sentence is perfect! No correction needed!

• Also, based on the same etymology, "ashi ga hayai" can mean that a product or something sells fairly well.
• Also, based on the same etymology, "ashi ga hayai" can mean that a product or something sells fairly well.