Preheat grill and oven each to 400 degrees.
Whisk together pineapple juice, honey, oil, and pinch of salt together in a large bowl. Add in chopped kale and toss until evenly and well coated. Set aside.
Mix the allspice, cinnamon, garlic powder, brown sugar, cayenne pepper, and salt into a small bowl.
Rub half the seasoning mixture on the pork. Place on grill and allow to sear 7-10 minutes and flip. Grill pork loin an additional 7 minutes or until internal temperature reaches 145 degrees. Remove from grill and allow to rest.
Place pineapple slices on grill and grill for about 3 minutes per side or until marks appear. Remove and set aside.
Meanwhile, use the other half of the seasoning blend to season the sweet potatoes and place on a greased baking sheet. Place in oven for about 20-25 minutes or until sweet potatoes are golden and are easily pierced with a fork.
Slice pork thinly. Top kale with pork slices, pineapple slices, sweet potato cubes, and diced avocado.