You'd have absolutely no need for a doggy bag if you opted to have your supper served in the Pack Away container. Designed by Debbi Nitsan, the product is a reusable bowl with a lid and a handle that has a body of expandable bellows.
Perhaps if you were to order a takeaway meal, the cook might be able to fill this plastic box for you, serving as a sort of 'lug a mug' initiative to reduce the waste produced by the fast food industry. You could easily bring this container with you since, when empty, the crimped sides buckle completely to flatten it out for convenience. Should you only have the appetite for a portion of your food, eat what you can and collapse the Pack Away to reduce unnecessary bulk.