Combine marinade ingredients, then add the pork. Marinade for at least 30 min.
Make the stuffing: Heat grapeseed oil in pan over medium-high heat, add garlic and onions and saute for 1-2 minutes. Add swiss chard and saute for another minute or so or until cooked and tender.
Add the pineapple and cook for about 2 minutes or until soft. . Remove from heat and season with sea salt and pepper. Allow the filling to cool a bit.
Remove pork from marinade. Slice a long cut into the pork loin creating a cavity. Stuff cavity with swiss chard mixture, then place on a pre-heated BBQ. Grill approx. 4-5 minutes on each side or until pork is cooked. Make sure to control BBQ heat so it isn’t overwhelmingly hot.
Remove pork from grill & allow to cool before serving. But don't wait until the pork get cold or else they'll get tough.