To express that a vegetarian dish is packed in a fast food box, you can use the following sentences:

1. This is a fast food box containing a vegetarian dish.

2. There is a meat dish and a vegetarian dish in this fast food box.

3. The dishes in this fast food box include a meat and a vegetable.

4. This snack box contains a protein source (such as meat) and a vegetable source.

5. The food in this snack box is balanced, including protein and vegetables. All the above sentences can clearly express the meaning that a vegetarian dish is packed in a fast food box.

Fast food is a convenient way of catering, which usually refers to meals that can be prepared and served quickly in a short time. Fast food usually adopts standardized and streamlined production methods to improve efficiency and reduce costs.