I've totally noticed the sodium thing as well. I was low then high and so on, never very stable with the numbers and the lower I was the more I lost, go figure,
So I've kept an eye on the numbers and it's coming along quite nicely as well.
Calorie issue here too, with the huge hunger decrease I went from my previous, eating like there's no tomorrow of about 3500cal to barely 1000. So I really have to work to pop over that 1200 but most days I do now because I am aware of what a great effect it has on my weight loss.