be off your food
be off (one's) food
To not be hungry or willing to eat, as due to illness. When I was sick, I was off my food for a week and lost a few pounds.
Farlex Dictionary of Idioms. © 2015 Farlex, Inc, all rights reserved.
be off your ˈfoodhave no appetite, probably because you are ill or depressed: She’s off her food, she’s sleeping very badly and she can’t concentrate.
Farlex Partner Idioms Dictionary © Farlex 2017