Heat the oil in a large wok or skillet over medium-high heat. Add the garlic and cook until fragrant, about 30 seconds. Add the ground pork and cook, breaking it up with a wooden spoon, until it is cooked through, about 3 minutes.
Add the soy sauce, sugar and white pepper and stir to combine. Add the rice and cook, stirring constantly, until heated through and lightly browned in spots.
Add the fish sauce, oyster sauce and chilies (if using) and stir to combine. Cook for another minute or two until everything is heated through.