Both are fine.

Raw kale has a bitter flavor that can be reduced by cooking it. Nonetheless, studies show that cooking it can reduce its nutrients, including antioxidants, vitamin C and some minerals. One study evaluated the effects of five cooking methods on the antioxidant and nutrient content of kale.

All cooking methods significantly reduced total antioxidants and minerals, including calcium, potassium, iron, zinc and magnesium, compared with raw kale. While kale may have the highest nutrient content, the study found that steaming retained the most antioxidants and minerals compared to other cooking methods.

So for those who prefer to cook their kale, steaming it for a short period of time may be the best way to maintain its nutrient levels.

Raw kale may be high in thyroid hormones

Raw kale may be more nutritious, but it may also impair your thyroid function. Kale and other cruciferous vegetables contain high levels of thyroid hormones, which are compounds that can interfere with thyroid function.

Specifically, raw kale contains a hormone called thyroid hormone.

This is concerning because thyroid hormones help regulate your metabolism. As a result, an underactive thyroid can lead to lower energy levels, weight gain, sensitivity to cold, and an irregular heart rate.