I don't wait for compliments. I told all my friends at work what I'm doing and how much I've lost.

My aunt, who's a psychologist, once told me that many people won't say something because they're afraid you might not like it -- your weightloss could be due to illness, or you may not have lost weight at all, etc. So as far as I'm concerned, I have to let them know that I'm happy with it so they can be happy for me too. Also, when they know that I'm trying to lose weight, they are more supportive and make a point of noticing.

And as Lilbug said, if they see you every day, they may not be able to see it because it's a gradual process.