Broccoli, leaves, raw has 28 kcal per 100 g, with 3 g of protein, 5.1 g of carbs, and 0.3 g of fat.
kcal per 100 g28
Values are from USDA FoodData Central, SR Legacy, FDC ID 169329 (opens usda.gov in a new tab). A food you buy can differ: check its label.