It's very difficult sometimes to change everything unfortunately.

True. That is why we should try to do small steps at least.

And then we should buy less in Mercadona (and other chains as well) but but but, even aware of the problem and having in mind my own experiment, I failed in my mission. I managed to go a few times to the fresh food market (en tres diferentes municipios porque tienen el mercadillo diferentes días) and buy there the vegetables and fruits but the other things I again bought in our familiar supermarket.