Appropriate/Reasonable Response
To tell or not to tell.
Ultimately is your business and yours alone.
I tell anyone who asks how I lost it. Most people comment on the weight loss, but then some want to know "what are you doing to lose it?" I follow up with "a whole lot of lifestyle changes including exercise and a lot less eating after my weight loss surgery in February". I frankly don't care if someone has something bad to say about the surgery because the fact is that I have been dieting for my ENTIRE life (yes I was a FAT KID) and this is the first thing to work for me. You can't possibly know me and not wonder what diet finally worked.
I am not ashamed or embarrassed or worried that someone will think I took the easy way out. HEY - guess what ... for me this is EASIER than most of the crazy diets I have done because I have a tool that helps make the weight loss easier. Go jump in a lake if you care that much about how I finally lost some weight. It's my health, my closet, my dinner plate and my life. If you are jealous because I lost it the easy way well too bad - that's your problem.
Good luck. Sorry about your MS - my best friend has it and it sux. I hope your work environment approves too!!