She said I was trying to fatten her up.
Were you actually trying to make her fat?
I'm going to fatten her up so she doesn't lose any weight
You shouldn't manipulate people into gaining weight or stop them from losing weight. You could cause them to develop heart diseases and risk long term complications.
I just want to get laid.
Well I think it's wrong to manipulate her weight just to have sex with her. You should let her eat whatever she wants and leave her alone.