Can we do such a system:

I register on the Carrefour website giving my credit card number. When shopping at Carrefour I pay using that credit card. By logging into Carrefour's account, I can check the list of purchased products for each of my purchases.

After log in to the Open Food Facts web page it downloads purchase history from my Carrefour account then it calculates total mass of saturated fats and sugars I bought in the last 12 months. On this basis Open Food Facts shows information whether I buy healthy food or not. In addition, I would like to know if I do not eat too much preservatives (Exxx) which are considered harmful.