Honestly, I will admit this feels manipulative.
Because if the only reason a girl was dating someone for free food, while not having the other person find out, would mean that too some degree she'd have to be putting on an act. Faking interest even though she really isn't interested, thus leading the guy on in thinking a relationship is possible. Which I personally feel is kind of messed up.
Especially since at least a few guys are willing to actually spend more money then they can really afford, not just on food but other gifts, in an effort to impress a girl. So considering how some girls might be taking advantage of that makes me kind of sick.