[tfgg]

It's the informal generic "you". More formally it'd be "Poor Sleep Gives One the Munchies, Study Says".

[kazinator]

Then the strawman-generator would just move the goalposts.

"Well, it says 'one'; that's a small number out of all the people in the study."

[oldmanjay]

"Poor Sleep Can Cause the Munchies" seems least ambiguous but also least punchy. If you can't read the fist, the headline missed.