Who do you think bought and cooked all the food he ate? Were they also to blame for Walter's obesity?
This question is to be answered on the basis of your own understanding, experience and thoughts. It is strongly recommended that you prepare the solution on your own. However, some sample solutions have been provided for your reference.
Walter might have hired a cook or maybe he stayed with his mother who cooked the food for him. Of course, these people were responsible for his obesity and are to be blamed.