Dinner problems

After advice from the vet to cut Tiny´s meals down to just 2 a day we have noticed a big and very worrying problem.
She now growls and snaps at anyone who goes near her or her food when she is eating. As her bowl is in the kitchen it is making it difficult for any of us to be in there while she is having her food. My daughter bought her a raw hide bone and she lay down in the front room eating it, but, when my daughter went to pass her she snarled. Usually she never bothers and will let you take biscuits from her, but now all this has changed.
Any help or advice PLEASE. Tiny is a very loving and gentle girl, but this sudden change has us very worried.

I have also posted this on the forums - behavioural problems section.