Our bodily fluids are made up of about 50 per cent water with about 0.9 per cent of mineral salts dissolved in it.

Ideally, this level must be kept constant in order to keep all our body functions running smoothly. If we enjoy more than one pint of beer we add a large amount of water (sorry for the bad news, but yes, most of it is water) but no trace of salt.

What our bodies really need is an extra supply of salt and that is why we crave peanuts, crisps and pretzel sticks--not because of hunger for proteins but in order to get the extra dose of vital salt.