When my girls are sick I'm more concerned that they're actually eating, due to lack of appetite, and that they're getting enough fluids.
For lunch I heated up roast pork tenderloin and roasted broccoli. My 15m wouldn't touch any of it but I wasn't concerned since she still nurses. 3.5 ate all the broccoli but no meat. She asked for cuties instead and I obliged.

Are you more lenient with eating habits when they're sick?