Agreed. It has an impact. And it helps you break through walls in training. But I think the authors of this article, who cite a previous study got a little car

Agreed. It has an impact. And it helps you break through walls in training. But I think the authors of this article, who cite a previous study got a little carried away. They cite a paper where researchers measured cleaning ladies after 4 weeks? You're not going from zero to hero in 4 weeks. How they ate over that period probably had a far larger effect on their overall health than mental positivity.