E.A.
My daughter was a great eater at that age, too. When she was 15 months old, my husband and I went away for the weekend and she stayed with my in-laws for two days. She doesn't see them as much since they live an hour away, and I recall the same thing happening during that time. She was out of her comfort zone and her whole schedule was thrown off! Don't worry, she'll make up for it when she gets back home with you!
Good luck. :)