I split the surcharge between COGS:Food and COGS:Supplies (paper goods) based on the weighting of those two items on the invoice.
Unless you just want to track the fuel surcharges for your own knowledge, you shouldn’t separate it. That charge is directly related to your food and paper procurement, and is therefore part of your COGS.
Same thing applies to shipping and freight costs. If you have a piece of equipment shipped, the freight costs become part of your cost basis.