I had business meals while on my fast. I just brought a container with my lemonade and went to the meal, ordered a glass of water with lemon when everyone else ordered their drinks, then had my lemonade while they ate.
I got a few raised eyebrows but explained to them that I was replacing my usual meals with a nutrient drink for a few days for health reasons.
Sometimes people wanted to know more and I explained the fast. Sometimes people just raised an eyebrow and moved on. I never experienced anyone acting like I was rude or behaving inappropriately.