When did Toriyama explain the Saiyans names?

[Ringworm128]

I'm looking for the interview where Toriyama explains why he based the Saiyan names on vegetables.

[El Diabeetus]

In Japanese there's no need for an explanation. Saiya (サイヤ) is an anagram of Yasai (野菜) which is Japanese for Vegetable.

[Herms]

There's a few places, but this one from Toriyama's joint interview with Takao Koyama and Masako Nozawa in the anime guide Tenka'ichi Densetsu might be the most thorough explanation:

Koyama:
There are still quite a few people who haven’t realized that “Saiya” is an anagram of yasai [vegetable]. When I tell them, they’re amazed.

Toriyama:
What, really? And here, I was embarrassed giving them the name “Saiya”. Like, “You just reversed the syllables in ‘yasai‘, didn’t you?” (laughs)

Koyama:
They’re also surprised that the Tsufruians come from “fruits”. (laughs) The Saiyans are vegetables, so you have “carrot” = Kakarrot, and even Nappa [Chinese cabbage] as-is. And, standing at the summit, you have the name of the category itself: “vegetable” = Vegeta. I really admired that.

Toriyama:
I made them vegetables as a reversal of the usual argument “they’re a warrior race, so obviously meat”.

(OK, I guess Koyama did most of the talking there, but still.)

While the Saiyan=vegetable name puns have been brought up in many places, I think this is the only place Toriyama explains the reasoning behind the whole name pun scheme itself: typically people would associate meat with a butch warrior race, so he inverted that and gave them a vegetable theme.