[BETSU-BARA]

It literally means 'other, separate(BETSU)' and 'stomach(HARA/BARA)'. So when someone say, 'Dessert is BETSU-BARA', it means 'I have room for dessert'. After BBQ, I was like almost full, but I always have enough space left for dessert.

AMA-I MONO WA BETSU-BARA DESU = I have room for somethig sweet