One more thing: I did that because I wanted to eat all the time. When I learned than sugar is addictive, I stopped.
Eventually I figured out it was the sugar filled ketchup that was doing it to me. Now I eat fries without ketchup and do not usually order additional portions (unless I am really hungry). Best of all, I do not feel like I am starving myself. When I do not have ketchup, I do not get the desire to eat more.
Less Salt water than you might think can kill you. Lower levels can also prove deadly when your body is stressed.
However, long term effects do seem limited.
I've had the same experience (and a few relapses, but I do know better).