I found this aphorism in my book of Korean aphorisms.
진잎죽 먹고 잣죽 트림한다 jin.ip juk meok.go jas.juk teu.rim.han.da vegetable-porridge eat-CONJ pine-nut-porridge belch-PRES [One] eats vegetable porridge and belches pine-nut porridge.
This means that you’re putting on airs. A poor person eats vegetable porridge, but the wealthy, upper classes eat pine-nut porridge. So you eat the cheap stuff and tell people you’re belching the good stuff.