I am trying my hardest to switch my 4 kitties from Purina Indoor Formula to Nutro Natural Choice Weight Management. At first, when I put the Nutro into their bowls, they LOVED it. The next day, they wouldn't touch it---just kept crying for food. I finally broke down and gave them some of the Purina Indoor formula b/c they were hungry and I felt bad. Does anyone have any advice about switching foods? Should I give up on the Nutro and try another? or keep trying to get them to eat it?