I go through phases like that. I do a combination of things. Drink tons of water and tea. Up my caffeine and nicotine intake, probably not the healthiest choice but they're both appetite suppressants. And give myself some sort of small barrier, like i have to do ten pushups everytime before i grab a snack, totally doable if I'm actually hungry but enough of a pain in the ass to cut down on randomly grabbing something.
I also stop buying most snacks, stock up on celery and carrots, it's easier to have self control in a grocery store then at home. Definitely makes me temporarily cranky when i just want a handful of corn chips but that passes quickly enough.