Add the olive oil to a large saucepan set over medium-low heat. Once the oil is hot, add the garlic and cook, stirring constantly, for 2 minutes. Add the ground turkey and using a spatula, break it apart into pieces while it cooks.
Once the turkey is fully cooked, add the tomato sauce, dried oregano, sugar, and a pinch of salt and pepper. Reduce the heat and simmer the sauce for 10 minutes then taste and season it with additional salt, pepper and sugar as needed.
While the sauce simmers, bring a large pot of salted water to a boil. Add the spaghetti and cook it until al dente, about 10 minutes. Drain the pasta then serve it topped with the turkey bolognese and a sprinkle of Parmesan cheese (optional).