How Do You Tell Someone They Are "Worryingly Thin" without shaming them?

It seems like there is every conceivable type of body-shamming nowadays, and people are very quick to make "fat-shamming, thin-shaming, fit-shaming (insert shaming type here) accusations at the drop of a hat. It's almost a pastime now to be continuously "outraged" or offended. That aside, how do you legitimately communicate to someone that they are looking too skinny or too fat or whatever your point of concern is without being vilified? How do you express concern without all of the faux outrage?   Images of Tara Reid in Miami were published today under various concerned sounding headlines: "Tara Reid Displays Thin Frame in Printed Bikini in Miami" - USMagazine "Tara Reid looks worryingly thin as she shows her bony rib cage and tiny thighs in a bikini on the beach in Miami" - TheDailyMail   Because the drama around being "offended" or being labeled a "shammer" creates a whirlwind of emotion that can very easily sweep aside even the most authentic and well placed concern. This got us thinking about the right way to handle this situation. What if it was a friend, a relative or even your partner? How do you communicate genuine concern about what is going on with someone else's body? Please share your thoughts below.