bmi isn't the whole story but it's a reasonable starting point. aim toward the upper end of that healthy 18-25 range, then once you're getting close you can decide exactly where feels right. a lot of it comes down to your natural shape and where you tend to carry weight. dropped my own number down into the low 20s and i'm genuinely satisfied with my results so far, might chase another 5 or so pounds but that's really it for me.