After dining at the Canteen several times, I received a Gourmet Voucher. Having used several Vouchers before, I know that the normal Vouchers make all the food options "fresh" and therefore more likely to activate the Felyne skills. How does a Gourmet Voucher then differ from a normal Voucher? I don't see anything extra that it could do.
From the Capcom forums:
Both types of vouchers can also be used as crafting materials.