Inches, metres, foot - I'm no good with measurements, but I'm pretty sure I was a size 24 or 26 inch waist in my late teens/early twenties - I still had to buy kiddies clothes with my slight build and 5"2 height. In my twenties I shot up to a size 14 when I went through bad eating habits and lifestyle, before coming back down in size to a 8/10. I still need to stop etaing crisps for brekkie, though, else the weight will be creeping back up!
Conne - anytime you can, take exercise. I'm not a fan of vigorous exercise, but I walk everywhere within reason. I never weigh myself, but I feel back strain when I am carrying more weight than my body would like. Oh, and do not use any silly diet methods, they will not benefit you in the long run.