Bring a large pot of salted water to a boil and cook the whole wheat spaghetti according to package directions until al dente.
While the pasta cooks, finely dice the chicken breast and pancetta.
In a small skillet over medium heat, sauté the pancetta until it begins to crisp and release its fat.
Add the diced chicken to the skillet with the pancetta and cook until the chicken is golden brown and cooked through, about 5-6 minutes.
In a small bowl, whisk together the whole egg, liquid egg whites, Pecorino Romano cheese, and black pepper until well combined.
Before draining the pasta, reserve about 0.25 cup of the starchy pasta water.
Drain the pasta and immediately return it to the pot or the skillet with the meat, keeping the heat on the lowest setting.
Quickly pour the egg mixture over the warm pasta while stirring constantly with tongs to create a creamy sauce without scrambling the eggs.
If the sauce is too thick, add a tablespoon of the reserved pasta water at a time until the desired consistency is reached.
Garnish with fresh parsley and serve immediately while hot.