Someone offered me a sweet the other day, this is not a rare offer and a while ago there was no way you'd catch me saying no thanks! Now though when I say 'No thanks I'm on a diet' I tend to get 2 different responses, the first being 'Oh sorry' not that there's any need to be. The second usually, 'what not even one/a little bit?' Erm no that's kind of the point of telling you I'm on a diet.
I know many people will think that one sweet or a tiny piece of cake or one biscuit won't harm your diet, maybe for some people it won't. I say no thanks though, not because I think that one thing will put on a pound or 2, but because one is never enough. If I have something off plan, or a treat day and still lose weight it makes it more tempting to have more next time and that's where it all goes pear shaped.
I'm not saying there's anything wrong with people offering, after all they're just being polite; for me though I have to say no thanks.
With my 13th weigh-in due tomorrow I am proud to say that for all those weeks I have been 100% on plan.