Personally, that would make me pretty mad, I'd feel like they were disrespecting me by doing that. That is where I would probably start swearing, lol.
I'd remove myself from those situations if possible. Especially the smell of food. I sometimes had to do that.
Talking to them so that they respect your wishes. Educate them on what fasting is really about and how safe it is.
Some people embrace the smells of foods and find strength in rejecting them with willpower (like cooking someone else a meal). I did that a few times. It almost a mind-body affirmation of what you want. But not everyone is like that.