If you're trying to go from a refined-carb spaghetti dinner to a balanced-carb version, try whole-grain pasta instead of whole-wheat pasta. It's an easier sell to your family, tasting milder than the latter.
Cook pasta according to package directions, omitting salt and fat. Drain pasta, and keep warm.
While pasta cooks, heat a large skillet over medium-high heat. Coat pan with cooking spray. Add onion, beef, and garlic; cook 4 minutes, stirring to crumble beef. Add zucchini and mushrooms; cook 10 minutes or until most of liquid evaporates, stirring occasionally. Place tomatoes in a mini food processor; pulse 4 times or until almost smooth. Add tomato paste, oregano, and red pepper to pan; cook 1 minute, stirring frequently. Stir in tomatoes; reduce heat, and simmer 5 minutes or until slightly thickened. Stir in salt and black pepper. Serve sauce over pasta; top with cheese.