Saw this a few months ago near 강남 at a place that served small portioned southeast asian fusion foods. I found it suprising that they would even mention this because I left hungry and wondering why I paid more than 15 000 for something that I'm pretty sure was a side dish at a normal Korean place. Anyways,
우리업소는 먹고 남기지 않을 만큼 적당한 양을 제공합니다
At our establishment, after eating, please leave an appropriate amount of leftovers.
Which, of course, is a long winded way of saying "Take all that you want but eat all you take."