It’s not really a grocery but more like a small gift. Marathons are often sponsored by local shops or larger companies such as pasta and biscuit manufacturers so in a way the participants become “ambassadors” for these brands and they are given what they call a “runner pack” which contains some of the sponsors’ products. Sometimes they also include fresh fruit, especially bananas since it’s good for runners to regain potassium after the race, as well as energy drinks!