>>/59951/
"Completely meaningless" is pretty strong. Social background and origin are at least partly controlled by control variables.
The study you posted is not as nuanced as it simply compares group mortality and does not analyse the foods themself. In any case, I do not know how it is in France, but most everywhere in the world the national nutritional guidelines advice eating very little meat, especially red meat, limiting saturated fat intake to >10% energy intake and emphasizing healthy vegetable oils rich in PUFAs, eating only low fat dairy in moderation, and eating a very plant based diet in general. Probably the biggest thing is simply eating more vegetables, fruits, nuts and seeds and abstaining from red meat and animal fats in general. That's probably where most of the gains come from. But for planetary health, I don't think there is any argument for the current meat-based food culture, it is simply unsustainable.