For as he thinketh in his heart, so is he

[tonychanyt]

People often take the above out of context. Let's see the context. Pr 23:

6 Eat thou not the bread of him that hath an evil eye, neither desire thou his dainty meats:

It's about a certain kind of man (M1) with an evil eye on his dainty meats.

7a For as he thinketh [H8176] in his heart, so is he:

This is about M1's thinking, not just any kind of man in general.

7b Eat and drink, saith he to thee; but his heart is not with thee.

He tells you to eat and drink but he does not mean it.

8 The morsel which thou hast eaten shalt thou vomit up, and lose thy sweet words.

You are wasting your time with M1. His morsel won't benefit you.

Pr 23:7a isn't about any kind of man universally. Moreover, the Hebrew original contained exactly one verb, not two:

Strong's Hebrew: 8176. שָׁעַר (shaar) — 1 Occurrence

Brown-Driver-Briggs:

שָׁעַר verb calculate, reakon (Late Hebrew Piel Jewish-Aramaic Pael put a valuation, estimate; Jewish-Aramaic שַׁעֲרָא interest, market-price; Arabic market-price is loan-word Frä189).

I like the NLT:

6 Don’t eat with people who are stingy; don’t desire their delicacies. 7 They are always thinking about how much it costs.

I know this kind of people because I was one of them I used to work as a cook in a Chinese restaurant. We ran occasional all-you-can-eat buffets. When a fat customer came in, I gave him an evil-eye look.

“Eat and drink,” they say, but they don’t mean it. 8 You will throw up what little you’ve eaten, and your compliments will be wasted.

It is more difficult to take Pr 23:7a out of the context in the New Living Translation.

On Biblehub, 9 versions used 'so is he' and 9 used 'cost'.