For meal prep, store the cooked taco beef, chopped lettuce, cheese, and toppings in separate airtight containers and assemble just before serving to keep the lettuce crisp. Keep avocado separate and toss with a little lime juice to slow browning if preparing ahead. You can substitute ground turkey or pork for the beef and adjust the seasoning to taste. For extra richness, add a drizzle of avocado oil or a few extra slices of avocado to each serving while still keeping carbs very low.