Kale is super nutritious and is extremely low carb. It is extremely nutrient dense, especially in Vitamins A, C and K1. Read about its benefits here.
To make it really tasty in an omlette, gently sautee a handful of kale in a good knob of butter with some salt until it has softened to your liking. Then add 2 or 3 beaten eggs and cook through. Great for a meal any time of the day.