Heat olive oil in a large non-stick skillet over medium heat.
Add diced onion, red bell pepper, and green bell pepper to the skillet. Cook for 4-5 minutes until vegetables are tender.
Add chopped spinach to the skillet and cook for an additional 1-2 minutes until wilted.
In a medium bowl, whisk the egg whites with salt and black pepper.
Pour the egg whites into the skillet with the vegetables. Stir gently and cook until eggs are fully set, about 3-4 minutes.
Add the cooked turkey sausage to the egg and vegetable mixture. Stir to combine and remove from heat.
Warm the tortillas in the microwave for 15-20 seconds to make them pliable.
Evenly distribute the egg, vegetable, and sausage mixture onto the center of each tortilla.
Sprinkle 1 tablespoon of reduced-fat shredded cheddar cheese over the filling in each tortilla.
Fold the sides of the tortilla over the filling, then roll tightly from the bottom to form a burrito.
Wrap each burrito individually in plastic wrap and place in a freezer-safe bag or container.
To reheat, unwrap a frozen burrito and microwave on high for 1-2 minutes, flipping halfway through, until heated thoroughly.