my grandpa's yan yan is even worse! She cooks alot for lunch (only grandpa and her) but my grandpa doesn't know how much she cooks. When my grandpa asks her to eat, she said no need too much! One day we went to visit grandpa, we found that the maid hid a big dish of food in the microwave. She would 'ding' it hot when my grandpa goes to sleep in the afternoon!!!
Also the soup, she cooks it for my grandpa and saves a big bowl for herself. And she adds water and reboils it for my grandpa!!! so bad!
give her some noodles, sausages, eggs & vegi. Ask her to cook that every day for lunch.
U can buy some 'cheap cheap' biscuits for her and ask her to eat them if she feels hungry during the day.
I provide food for my maid for lunch & dinner to cook, and she only cooks noodles for lunch and eat 1 piece of white bread. My maid takes 5 mins to cook + 5 mins to eat!!!
I have asked her to cook more, she said ok. Even she has eggs, chicken wings, fish, vegi, etc...she only cooks them for dinner. (1 dinner, she cooks 1 meat / fish / egg and we share our cooked vegi with her)