So this isn't really about France in particular. Rather, the author is pointing out that France and Switzerland historically consumed more calories than the US with much lower obesity; and the fact that they probably got more exercise is irrelevant. The French began becoming obese around the 1990s but the Swiss never did. The article points to the difference in fat types: the US consumes a lot of polyunsaturated fats (PUFA) while the Swiss... don't.

Currently in the US, the party line is still that PUFAs are generally good, I think largely because the gov is still fighting to get rid of trans fats, which are definitely bad. PUFAs come from sources like soybean / corn / sunflower oil; but also fish, which is generally regarded as one of the healthiest foods.

Beyond that... this blog is hosted on some kind of ecommerce site. So it's interesting, but as a source, pretty questionable. On the other hand, the "official" sources (e.g. American Heart Association, USDA) have screwed up so frequently and thoroughly on nutrition that I doubt anyone should trust them for a few decades.

Anyone have a source / studies that may back up anything on this blog?

Interesting ! As an anecdote, I have tried to put a bit more weight by starting the day with three croissants and it hasn’t been really working.