How To Compliment Others

After reading some humiliating experiences from other MyFitnessPal'ers (see "your worse or humiliating experience when fat?" at http://www.myfitnesspal.com/topics/show/1190906-your-worse-or-humiliating-experience-when-fat), I wonder if others out there have suggestions on something along those lines.

I've never been overweight on the BMI charts, but when I see other people's struggles with weight and their efforts to control it, I'm impressed...and I'd like to say so. Often times, as I see overweight or obese people out walking, jogging, or doing other exericse, I wish there was something I could call out to them that won't be taken wrong--something that would say "good job!" rather than something that would seem like I'm mocking them.

If I call out something like "Way to go--Keep it up!" from the other side of the street, it could be taken as a sarcastic insult. Same for something like "We can do this...it's worth it!" as I pass someone running along the trail while I'm running or while I'm on my bike.

Even a longer statement if I slow down to be beside them long enough to say it..."You're obviously overweight, but you're out here exercising. I'm impressed." As sincere as I may be, it could show up as the next post on http://www.myfitnesspal.com/topics/show/1190906-your-worse-or-humiliating-experience-when-fat.

Any suggestions?--What can a person call out that encourages you rather than humiliates you? Or is it better to just shut up entirely and not let the person know you even noticed his/her efforts?

Thanks