Bring a pot of salted water to a boil and cook the whole wheat spaghetti according to package directions until al dente.
While the pasta cooks, whisk the whole egg, egg whites, grated parmesan cheese, and black pepper in a small bowl until the mixture is smooth and well combined.
In a large skillet over medium heat, sauté the diced pancetta until golden and crisp, then add the minced garlic and cook for 30 seconds until fragrant.
Add the zucchini noodles to the skillet and sauté for 1 to 2 minutes until just tender but still bright green.
Drain the pasta, reserving 2 tablespoons of the starchy pasta water, and add the hot pasta to the skillet with the pancetta and zucchini.
Turn off the heat completely and quickly pour in the egg mixture while stirring constantly to create a silky, creamy sauce using only the residual heat.
Thin the sauce with the reserved pasta water if needed, season with sea salt, and serve immediately while warm.