well i think it is the valueof nutrition in food. so if you eat lettuce, lettuce has fibre and water in it (majoriy)..
so the nutritional value would be higher (fibre and water are good for you!).
nutritional value means to find the nutrients in a food eg. lettuce= water and fibre well the majority of it so i hope i helped you with this question if i didn't please improve it :) :) :) :)