I have four people working for me who fast daily, family and countless other people i am in contact do fast. I see as ritual and i like the part of that brings the community together and charity. simply im very understanding and I do my best to make it easy for those working for me ( give them less work and more time for prayers)
do they know im not fasting? Yes, Do I care what they think? No. out of respect i don't eat front of them same as i will not eat front of Hungry and thirst beggar.
now and then i meet noisy people who try to make me guilty or try to give me sermon, normally i will give simple answer if they ask if im fasting which is simply NO, majority will be satisfied with that answer, those who don't have boundaries who push i make sure they don't ask again without explanation.
my take is no need to pretend. act as you will act normally and respect those who see things differently and expect same treatment from them without you defending the way you see things.