Healthy at home, at dad's not so much....
I have full custody of my kiddos, but they go to their dad's every other weekend and occasionally once during the week. We eat mostly organic, lots of fruits and veggies, no red meat. My daughter who is 8 has eaten fast food once in her life, and my son who is 11 has had it a few times.
When they go to their dads, he feeds they HORRIBLE food. I know it's not going to kill them, but they come home feeling sluggish and sometimes even get sick. My daughter has food allergies which he doesn't believe to be "real" even seeing the dr results.