New Measured Weight for One Cup Raw Kale Reduces Nutrient Intake of Individuals Following the Wahls™ Diet

Kale is a nutrient-dense, dark-green leafy vegetable often eaten raw in salads or added to smoothies. The USDA National Nutrient Database for Standard Reference Release 26 reports the weight for one cup raw, chopped kale as 67 grams, among the highest for raw leafy vegetables. Objectives: Measure the weight of one cup moderately packed raw kale with stems and tough midrib parts removed and evaluate the impact of the new cup weight on nutrient intake of individuals consumingraw kale. Methods: Six staff members measured curly and lacinato kale using standard procedures and 14 study participantsconsuming 4-6 cups raw leafy vegetables/day measured one cup curly kale in their usual manner. Twenty-seven dietary recalls obtained from participants following the Wahls™ diet were entered intothe Nutrition Data System for Research and then recalculated using staff-measured curly kale cup weight. Results: Mean(SE) staff cup weight for lacinato kale was significantly higher than curly kale [21.3(1.4)g vs 16.0(1.4)g; p<0.0001]. Percent refuse was also higher for lacinato kale [mean(SD) 42.0(11.4)% vs 28.5(3.9)%; p=0.012]. Mean(SD) weight of moderately packed participant-measured cups [17.5(6.4)g]was similar to staff cup weightbutfirmly packed participant cupsweighed more [46.4(4.1)g]. Intake of vitamins K, C, A, manganese, copper, and folatewere significantly lower for diets calculated with the staff cup weight (p<0.0001). Conclusions: The new measured cup weight of raw kale is lower than previously reportedand reduces nutrient levels in diets containing raw kale. Verification of cup weights for other raw leafy vegetables may be warranted.