A mysterious pop-up shop emerged in Tokyo’s famous Harajuku district in May, offering passers-by free vitamin supplements – as well as an educational experience.

The supplements, neatly stacked on shelves akin to a science laboratory, were designed to give people the nutrients they weren’t getting from eating fast food – such as burgers, pizza, fried chicken and ramen – which are in rich supply across Harajuku, an area renowned for its vibrant youth culture.

The free vitamins and other nutrients at the Fast Food Aid shop were available to anyone producing a receipt for a fast food purchase. After handing over their receipts, customers were served by staff dressed as pharmacists, who would proceed to analyse the diner’s intake based on the receipt and produce a bottle of vitamins and nutrients to supplement what was missing.

A slogan etched across the shop exclaimed: “To fast food lovers who are also health conscious – no need to worry! Just take our supplements after eating your fast food.”

The stunt was, perhaps surprisingly, organised by a restaurant company called Dohtonbori, working in partnership with design studio Kaibutsu, which created the shop.

Dohtonbori itself is classed as a fast food chain, but rather than offering the likes of ramen (noodles) or gyudon (a beef and rice dish), its menu consists of okonomiyaki and monjayaki – savoury pancakes that are considered a healthier option thanks to fresh vegetables being a crucial part of the dish.

The purpose of the stunt became clear to anyone who had eaten at Dohtonbori and then visited Fast Food Aid to supplement their intake: the medication bottle for okonomiyaki would be handed over empty, accompanied by the words “Looks like fast food, but you need zero tablets.”