Bioavailability isn't the while story: some foods can be too bioavailable (and not great for you when consuming too much) such as sugars which can cause your body to form inappropriate hormonal signals and disrupt normal satiety. (Looking at you, fructose!) Additionally, there are literally thousands of antinutrients, toxins, carcinogens, and endocrine disruptors that simply aren't accounted for in normal nutritional analyses.