It's a common dilemma:
You know someone is dieting, but you aren't really sure. Also, you aren't sure if they lost weight. But you don't want to insult them by not saying anything.
I have been on a diet for a while. I have some weight to lose, and I am trying to use the time that I am not in shidduchim to slim down a little.
But nobody is perfect (and I'm nobody which means I'm....) and I don't always eat the way I should. (No, please don't tell the shadchanim!)
So anyway, people are aware of my dieting efforts. And they constantly praise me for my efforts, telling me how good I look and how impressed they are and how I am shrinking and I am fading away to nothing and they are so impressed at my self control and....and....and.....
I hate when they go on about it, but I hadn't lost any weight. It makes me feel really dumb. I get all squirmy, wondering if it is rude to correct them, tell them I really didn't lose any weight. And that I had actually just eaten something I really should not have eaten ten minutes before this conversation. It also invalidated other compliments they give me. If they are telling me that I look like I lost a ton of weight when really I hadn't lost any, then obviously they aren't sincere when they tell me that they love my new shoes, or that my cake that I baked is delicious....
But on the flip side, it's also insulting not to say anything, in case I really did lose weight. "You mean to tell me you didn't notice that I lost weight?!"
So here is my solution. You know someone is on a diet, she looks good but your not sure if she really lost weight or not, so you say:
"You look really good"
Yep. Simple as that. If the person lost weight, they will tale it as a compliment on the weight loss. If the person didn't, they might say something along the lines of "well, I don't think I lost much weight since you last saw me, but thanks anyway."
And you get to pat yourself on the back knowing you solved a dilemma. And celebrate by eating an ice cream, preferably in front of your dieting pal, to test their willpower.