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:
Vouchers give a free meal and make all the ingredients fresh. Gourmet vouchers do this as well, and causes all of the skills shown to activate.
Both types of vouchers can also be used as crafting materials.