I work at a pharmaceutical company for animals and all our interactions with colleagues are on site. There is this particular colleague who carefully observes my pattern and constantly gives me lecturing. I am a very simple person in general. I eat often the same thing (toasts or something made fast) at work and drink mostly cola zero at our lunch break.
This particular colleague constantly whines about it or gets even toxic, for instance how unhealthy I live, how bad cola zero is etc. It doesn’t stop there tho, he will gladly criticise my hair looks, or my clothes or if my car is not washed etc. It stretches to quite personal stuff sometimes.
However I have reached a point where I constantly think what he will say to me and it eats me up even outside of work.
I am a very quiet guy generally and want to avoid any form of conflict. How can I deal with him?
Thank you!