If you are considering reminding a fat person that they are fat, you need to ask yourself what your motivations are for doing something which (1) will certainly cause short-term emotional pain; and (2) is unlikely to result in the person getting their shit together and losing the weight. Are you really trying to help them? Or are you just trying to make yourself feel superior at their expense?

Remember that we're discussing a case where the person asked you for your opinion. I certainly wouldn't just randomly say to someone "Hey, guess what? You're fat", especially if that person was my friend or someone else I cared about.

But if they asked me? That's a different story altogether.

My impression is that there are a lot of "concerned" people who are happy to give free advice to fatties (often something along the lines of "eat less and exercise more -- you're killing yourself") but unwilling to give $20 or $30 towards a gym membership for said fatties. This suggests that often the motivation is more status-mongering than actual concern.

Do you really think this is the case for good friends, or loved ones? Unwilling to give $20 or $30, really? And furthermore, do you in fact believe that not having the money for a gym membership is the important obstacle between an overweight person and an effective weight-less solution?