Manufactured foods aren't remotely comparable. We're taking two ancient food types: vegetables and meat, and comparing children's reaction.
Meat is highly nutritious and has every macro nutrient you need to survive. Vegetables are loaded with plant toxins (phytic acid, lectins, oxalates, etc.) and provide nearly 0 digestible macronutrients and most of the micronutrients aren't absorbable anyway due to the anti nutrient load.