Skip the chain restaurants when grabbing food to-go. Head over to the local restaurants with neighborhood flair and intimate staff. In most cases, there is an owner or manager on duty that can vouch for your zero waste requests.
Top of the list is The Pullman (Kirkwood) they explicitly say on their website that you can bring your own containers for to-go food, and even charge 50 cent for disposable containers. This makes you contemplate if they disposable ware is worth the cost (literally and figuratively).
Some of my other favorites are Dulce Vegan (Kirkwood), Tassili's Raw Reality (West End), We Suki Suki (East Atlanta Village) and Stationside (West Midtown). I recommend sitting at the bar, because it eliminates the whole dine-in theatricals. You can order your food 'for here', then pack it up yourself in less that 20 minutes.
If you're not near a welcoming neighborhood location, seek out Panera Breads. You can always order 'for here' then pack your food yourself.