In http://canonical.org/~kragen/comida.html I calculated the costs of some minimally adequate diets on 2012-08-16. So now I want to update the cost calculation for at least one of them to current prices.
The “minimal budget for balanced macronutrients”, for 2482 kcal per day with 52% from carbohydrates, 18% from protein, and 30% from fat, consisted then of 200 grams per day of soybeans, 5 grams per day of salt, 33 grams per day of sunflower oil, and 430 grams per day of white flour. Coto Digital offers 500 g of soybeans for AR$14.99, 1 kg of Cañuelas 000 white flour for AR$7.72, 1 kg of salt for AR$41.65, 1 kg of medium-fine salt for AR$17.19, and 1.5 ℓ of sunflower oil for AR$49.75.
| Food | size | AR$ | price/g | g/day | AR$/day | % of cost |
|----------+------+-------+-------------+-------+-----------+-----------|
| Soybeans | 500 | 14.99 | 0.02998 | 200 | 5.996 | 56.055567 |
| Flour | 1000 | 7.72 | 7.72e-3 | 430 | 3.3196 | 31.034366 |
| Salt | 1000 | 41.65 | 0.04165 | 5 | 0.20825 | 1.9468932 |
| Oil | 1400 | 49.75 | 0.035535714 | 33 | 1.1726786 | 10.963169 |
|----------+------+-------+-------------+-------+-----------+-----------|
| Total | | | 0/0 | | 10.696529 | 100. |
#+TBLFM: $4=$3/$2::$6=$4*$5::$7=100*$6/@6$6::@6$6=vsum(@2..@5)
So at supermarket prices, this diet would now cost you AR$10.70 per day. Maybe if you buy in bulk the prices would be lower; and on MercadoLibre, you can buy 30 kg of soybeans for AR$466, which works out to half the price of the supermarket.
However, this is 3¾× as much as it cost when I originally did the calculations, in Argentine pesos. (I don’t have a good set of CPI figures to adjust the inflation with, because during the previous administration the integrity of the statistics bureau was destroyed, and they were forced to publish false numbers.) At the time, the dollar sold for AR$6.26, and this diet cost AR$2.86 per day, which works out to US$0.46 per day. Now, the dollar sells for AR$16.00, more or less, so this works out to US$0.67 per day. This represents a substantial loss of buying power in Argentine necessities for the dollar, and the popular feeling is that hours of labor have also lost substantial buying power.
With only three foods (not counting the salt), the proportions of the foods are set by the macronutrient balance requirements I’ve chosen; there is no wiggle room to reduce the price by changing the proportions slightly. But it might be the case that some other combination of foods is now the optimum — I doubt it, though, because the proportions are almost the same, except that now the oil makes up a bit more of the cost (11% instead of 6%) and the flour correspondingly less. So probably none of these foodstuffs have increased in price proportional to the market as a whole, and I think the flour is maintained at an artificially low level by government subsidies paid to supermarkets, reducing malnutrition at the cost of encouraging people to eat too much flour.
This implies that a family of four will be malnourished if less than about AR$42.80 per day is spent on their nutritional needs, at supermarket prices; this works out to AR$1302 per month for the four.
For an actually healthy diet, you almost certainly need some fresh vegetables, even though the flour is supplemented with vitamins and minerals to prevent deficiency diseases. If bought retail, this adds substantially but not overwhelmingly to the cost; for example, carrots cost AR$17.90 per kg at Coto, so 100 g of carrots would add an additional AR$1.79.