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Low Calorie Meal Prep Spaghetti Squash & Marinara Chicken - Simple, Satisfying, and Weeknight-Friendly

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Prep Time 15 minutes
Cook Time 35 minutes
Total Time 50 minutes
Servings: 4 servings
Ingredients Method

Ingredients
  

  • 1 large spaghetti squash (about 3–4 pounds)
  • 1–1.25 pounds boneless, skinless chicken breasts (or thighs trimmed of excess fat)
  • 1 tablespoon olive oil
  • 1 small onion, finely diced
  • 3–4 garlic cloves, minced
  • 1 (28-ounce) can crushed tomatoes or tomato puree
  • 1 (14.5-ounce) can diced tomatoes (no salt added if preferred)
  • 2 tablespoons tomato paste
  • 1 teaspoon dried oregano
  • 1 teaspoon dried basil
  • 1/2 teaspoon red pepper flakes (optional)
  • 1 teaspoon sugar or a pinch of baking soda (to balance acidity; optional)
  • Salt and black pepper, to taste
  • Fresh basil or parsley, chopped (optional, for garnish)
  • Grated Parmesan or shaved pecorino (optional, for serving)
  • Nonstick cooking spray

Method
 

  1. Prep the oven and squash: Preheat your oven to 400°F (200°C). Carefully slice the spaghetti squash in half lengthwise. Scoop out the seeds with a spoon.
  2. Season and roast: Spray the cut sides lightly with cooking spray and season with salt and pepper. Place cut-side down on a parchment-lined baking sheet. Roast for 35–45 minutes, or until the flesh is tender and easily shreds with a fork.
  3. Start the sauce base: While the squash roasts, heat the olive oil in a large skillet over medium heat. Add the diced onion with a pinch of salt and cook 3–4 minutes until softened. Stir in the garlic and cook 30 seconds until fragrant.
  4. Add tomatoes and seasonings: Pour in crushed tomatoes, diced tomatoes, and tomato paste. Stir in oregano, basil, red pepper flakes (if using), and a small pinch of sugar or baking soda to reduce acidity. Season with salt and pepper. Simmer uncovered on low for 15–20 minutes, stirring occasionally, until slightly thickened.
  5. Cook the chicken: Pat the chicken dry and season with salt and pepper. You have two options: Skillet: Add a touch of oil to a separate skillet over medium heat. Cook the chicken 5–6 minutes per side, until cooked through (165°F/74°C). Rest 5 minutes, then slice or dice.
  6. Poach and shred: Simmer chicken gently in salted water for 12–15 minutes, then shred with forks. This keeps it lean and tender.
  7. Add chicken to sauce: Stir the cooked chicken into the marinara and simmer 5 more minutes so flavors meld. Taste and adjust salt, pepper, or herbs as needed.
  8. Shred the squash: Remove squash from the oven and let cool a few minutes. Use a fork to scrape the flesh into long strands. Transfer to a bowl and season lightly with salt and pepper.
  9. Assemble for meal prep: Divide the spaghetti squash among 4–5 meal-prep containers. Top each with a generous portion of marinara chicken. Add fresh basil or parsley if you like. Finish with a sprinkle of Parmesan, if using.
  10. Let it cool: Allow containers to cool with lids off for 10–15 minutes before sealing to avoid condensation.