How can you prevent over snacking while studying for exams?

Whenever I'm studying for an exam, I always have a tendency of overeating or over snacking on something, which isn't really helpful because I'm trying to lose some weight...

Do any of you have some tips as to how to prevent overeating or not eating at all while studying for an exam? I just binged on like three bowls of chicken noodle soup while trying to study for an accounting exam...:/
How can you prevent over snacking while studying for exams?
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