ワードアップ英会話 WORD UP ENGLISH CLASS | 日記 | Idioms: "food for thought"

To say something is "food for thought" means that it is an interesting idea, and is worth thinking about.

Here's an example conversation:

Jack: Do you want to go see a movie on April 1st?
Wendy: Well, if the weather's nice I might want to go look at cherry blossoms.
Jack: That's a good point, but don't forget, movies are only 1000 yen on the first day of the month.
Wendy: Well, that's food for thought. Let me check my schedule and get back to you.

Here, when Wendy says "that's food for thought," it means she hadn't thought about the discounted movie tickets. Now, considering the cheaper price \, going to see a movie seems like a better idea, and she wants to think more about it.