Lena ate most of the food that Samuel had brought for her. Less because she was hungry and more because she hoped that it meant that he would stop worrying about the fact that she hadn't been eating. Everyone acted differently when they were overly stressed and for the princess that resulted in her not eating.
She had nothing against food, to her when there was too much going on it just became an unnecessary time sink that she could cut out in order to focus on other things. Besides, she ate enough during other times around the stressful one she didn't really think it affected her all that much when she had moments such as these.