I date all the time and would NEVER mention it. Guys do not want to hear about anything "heavy" in your life which would include your weight issues, family, money or work problems...they want to hear about what you like, what you are passionate about, how you spend your time - I would never go on a date skinny or fat and talk about my weight issues. If they are my BF - and MONTHS have gone by, I would tell them.
So how do I handle eating? Guess what ? They don't really notice. I'm 5 months out and I eat pretty normal - I order the best most healthy thing on the menu for me, I eat my protein first and do the best I can - I also eat really slowly...they just really don't pay too much attention.