Work lunches are my specific nightmare. My company does team lunches every Friday and there's this unspoken pressure to order a "proper meal" and eat it all. I've been ordering salads and getting comments like "oh are you on a diet?" with that tone, you know the one.
What I've started doing: ordering something substantial-sounding (like grilled salmon with vegetables) and just eating what I can. If anyone comments, I say "saving room for dessert" and then conveniently never order dessert. Nobody notices.
Also — sitting next to the office big eater helps. They'll happily take your leftovers and it looks like you finished your meal 😂