| What I would have liked to see and which should exist in the full paper, but it is not described in the summary or in the snippets, is the exact method used to compute the score for a given diet. It is not possible to compute any kind of valid score for an aliment taken in isolation, because no aliment is healthy if one would eat only that. The various aliments complement their contents of nutrients and a pair of certain aliments can be very healthy, even when eating only one in the absence of the other would be unhealthy. Moreover the quantity of an aliment matters a lot. For small quantities, most aliments are neither healthy nor unhealthy, they do not provide any noticeable contribution, positive or negative. For medium quantities, an aliment can be healthy or unhealthy, depending on which are the other components of the diet. For large quantities, almost any aliment becomes unhealthy. So computing a realistic score for a daily diet is quite difficult and just giving vague guidelines like eating "mostly" vegetables with "a little" animal protein, while correct is completely unhelpful for providing any quantitative conclusions. I hope that the full paper includes a valid methodology for characterizing a diet, but I somewhat doubt this, because I have never seen such a precise methodology yet. The first step for computing a score would be to have for each component of the daily diet both the daily intake and the array of values with its content for all of the about 50 essential nutrients that are required by a human to live. The content values should take into consideration the digestibility of that aliment by humans. Then by multiplying the nutrient contents with the daily intakes, one would obtain an array of about 50 values with the daily intakes for each essential nutrient. For each nutrient there is an optimal range for the daily intake, and the values that are either higher or lower must be penalized the farther they are from the optimal range. To this initial score, various correction factors must be applied. The food must require a certain amount of chewing effort, in order to preserve the health of the teeth. If that is not true a diet must be penalized. The food must contain some amount of indigestible fiber, to help the transit through the intestine. If that is not true a diet must be penalized. There are many vegetables or fruits for which there is decent evidence that they contain something that improves health, especially cardiovascular health, but it is unknown which are the exact substances with favorable effect and which is the mechanism that explains their action. A diet containing such vegetables or fruits should be scored better. |