1. Every junk food supplier knows to load their product with salt
to increase sales.
2. I caution against assuming that ion transport mechanisms in
the intestines are the sole determiner of appetite. Some people
convert absolutely everything they eat into fat. Increasingly,
they are having an operation to remove 80% or so of their
stomach. The original idea was that patients would be physically
incapable of eating enough to make them fat, but it has been
found that most of those patients simply don't feel hungry any
more. Clearly, the stomach plays a significant role in
determining appetite.