I would have to agree, I don't own a set of scales.
Likewise, if my clothes get tight, I know I have put weight on. I'm not much of a dieter, I have no will power. I used to weigh around 12 st. At 5"4 that is possibly a bit overweight, I'm not sure. But 3 years ago I had severe food poisoning twice in 2 months and lost 2 stone in about a month. Luckily I haven't put it back on. But to be fair, my weight generally doesn't bother me.
(don't try it, none of us realise how dangerous food poisoning is, i know someone who almost died because of it, and has been left with very bad mobility, has to get injections twice weekly in order to stay mobile - not recommended)