How can transaction metadata be added to payments?

Many payment protocols have reserved or message fields, which can be utilized. The question then becomes, how does one implement a global system into such a protocol which is universally understood?

In some reserved field, you could parse a value like: 02948473957

Where 02 could be category of Food
94 Chinese Foods
8473 - a particular sub-reference
and 957 - calories consumed.

Couple of points worth pondering upon:

• What would be difficult is to understand if 957 calories were for the total on the bill amount or for a particular person?
• What happens when the reserve field is already being used?
• How long before a global consensus is achieved for the meta data codes?
• How will devices and sales system push this data out onto the bill itself?
• It took years and years of work 100,000s of man hours, just to put the Harmonized System Coding system together. That was because of a Trillion dollar shipping and cross-border trade industry problem.
• What problem does the meta-data solve?
• An easy way would be to program your POS terminals so that when a soup item is added to the bill, on the printable receipt the information can be printed on the calorie count, this would vary from vendor to vendor but can be done, however it would be localized.