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. Sauté for 4-5 minutes until vegetables are softened.
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, black pepper, ground cumin, and chili powder.
Pour the egg whites into the skillet with the vegetables and cook, stirring gently, until the eggs are fully set, about 3-4 minutes.
Add the cooked lean turkey sausage to the skillet and stir to combine with the eggs and vegetables.
Remove the skillet from heat and set aside.
Warm the whole wheat tortillas in the microwave for 15 seconds to make them pliable.
Divide the egg mixture evenly among the 6 tortillas, placing it in the center of each.
Sprinkle 1 tablespoon of reduced-fat shredded cheddar cheese over the egg mixture on each tortilla.
Fold in the sides of each tortilla and then roll tightly to form burritos.
Wrap each burrito individually in plastic wrap or aluminum foil.
Place wrapped burritos in a freezer-safe container or bag and freeze for up to 3 months.
To reheat, remove the plastic wrap or foil and microwave a frozen burrito on high for 2-3 minutes, turning halfway through, until heated through.