Heat a large skillet over medium-high heat. Cook and stir ground beef, onion, garlic powder, onion powder, salt, and black pepper in the hot skillet until browned and crumbly, 5 to 7 minutes; drain and discard grease.
Return skillet to burner over high heat. Add water; cover skillet and bring to a boil. Stir macaroni into the boiling water-ground beef mixture; cover and lower heat to medium. Cook, keeping covered, for 5 minutes. Stir, cover, and cook until macaroni is tender, about 5 more minutes.
Stir processed cheese food into ground beef-macaroni mixture until melted. Remove from heat; stir in sour cream.
1/2 pound lean ground beef, or more to taste
1/2 small onion, minced
1 teaspoon garlic powder
1 teaspoon onion powder
1 pinch salt and ground black pepper to taste
2 cups water
2 cups elbow macaroni
8 ounces reduced-fat processed cheese food (such as Velveeta®), cut into small pieces
2 tablespoons reduced-fat sour cream, or more to taste