I lived in high heals. Pregnant? high heals. Grocery shopping? high heals. Until the day that my body said- no more high heals. I cannot wear them anymore. I have come to realize in my research and journey with chronic knee and hip pain, that high heals probably caused me body alignment problems that affected me far beyond mere foot pain. Your co worker is an idiot. Don't debate it with her. But know that its true that heels wreck havoc on body alignment resulting in all kinds of pain and disfunction.
http://www.macleans.ca/society/life/teetering-on-the-brin...
Had I read the article above while being a high heal lover, I would have said "bahh humbug! poo poo and piddle piddle". But now with a chronic knee injury, pelvic floor problems, and a host of other ailments all attributable to poor alignment, I realize that I did myself a great deal of damage wearing heals all the time. Your coworker may or may not notice the damage she has done until she is much older. It is mostly woman getting knee and hip replacements, and this is linked to positive healed shoes (not just high heals, but positive rise in the heals over .5", so even men's dress shoes). Turns out that looking tall and sexy comes at a price. Your friend will probably not accept that information because the need to feel attractive will cause her not to take it to heart. So again, don't even bother debating. You know that your body has said no to heals. Listen to your body, not your coworker.
(FYI, I have a high, yet collapsing arch. )