Same here. I will give her a portion of the dishes (normally more than one meal portion) and she can finish it all in one meal or have left over for the following meal (I've done the same for myself too).
Same: 開飯前, 由我夾比佢, so far so good, all of my helpers gain weight after working for me.
I know an employer "叫佢自己夾夠自己果份", the helper got a chicken thigh and wing for herself. As a guest, I was so surprised that the chicken had only one thigh & one wing when the helper took out the chicken. Kind of joke for the guests and feel embarrassed for the employer.