Dog Proves McDonald's Fries Taste Way Better with Ketchup

This pooch went from not lovin' it to REALLY lovin' it ... and all it took was a little Heinz-sight.

Let's face it ... McDonald's has some of the best french fries out there in fast food land, but plain 'ol fries aren't cutting it for this German Shepard mix. The K-9 turns its nose on the naked fry.

But then ... the owner ups the game with the condiment of choice -- ketchup. The dog attacks the partially red target ... gobbling it up with no reservations.

We got to wondering ... is this a good advertisement for Mickey D's? Humans dig fries even without ketchup, but we're guessing the majority of dog owners prefer their fries with the red stuff.