It is a common action for people who overeat or have special dietary restrictions.

My grandfather had to eat right for his heart condition, but he couldn't trust himself while half asleep. Just using willpower wasn't enough, since he couldn't think to exercise willpower in that state. The solution was to lock up the fridge and pantry at night, and make getting his copy of the key difficult enough to wake himself up fully. If one was more cynical, it also meant he couldn't just stay up and cheat, then blame 'sleep-eating' either.

Regardless, it got results and in the end that's what matters.