Place shredded carrot and zucchini on a clean towel and wring out as much liquid as possible.
Place strained carrot and zucchini in a bowl and add ground beef, ground pork, parmesan, onion, parsley, salt, pepper, garlic powder, breadcrumbs, and eggs. Mix until just combined.
Grab about a ¼ cup (85 grams) of the mixture and roll into a ball.
Pan-fry the meatballs in a large pan over medium-high heat until all sides are golden brown, about 10 minutes, then add the marinara sauce and simmer for 10-15 minutes. Or, can bake the meatballs on a parchment-lined baking sheet at 350˚F (180˚C) for 30-35 minutes, flipping after the first 15 minutes. Warm up marinara sauce and serve on the side.
Serve the meatballs with cooked spaghetti and Parmesan cheese.