I think I understood it. I just feel it's a generalization that's become a platitude and is not true for everyone. (Similarly to the "you need to sleep 8h per night" or "drink 8 glasses of water per day). For me, (as an example) it's way easier to do 1h/exercise per day than to change my already healthy diet and cut calories b/c I am a pretty small female who doesn't need many calories to begin with to maintain weight (as compared to a guy who is 1,80m for example). That's why I said it's a platitude that's I don't believe to be "true." You could also say it takes too much time and dedication to track food, cook from scratch and other things diet related that many fitness people promote. I found that to be way, way more exhausting than moving my body for an hour a day.