Trade emails with the kitchen manager - and get HR's approval ahead of time. The healthier people eat, you'd explain, the less sick time the organization might see. With their blessing, see if the kitchen manager can make a healthy offering one day a week. Call it Wellness Wednesday or something like that. And, for snacks, see if they could order packaged almonds to put in with the chips, candy, etc. At least that alternative would be available.
Resolve to Evolve