Cravings

One thing I've  noticed, and found rather bizarre, during my marathon training is that I am craving certain foods.  I feel like I've run enough in the past that I would have experienced something similar, but no. 

What am I craving?  Salty foods.  Pretty much anything with salt sounds good.  Also, cheese.  Anything with cheese on it makes it taste that much better. 

I eat more or less the same food every day.  I don't buy things that are "bad for you" because I like to eat healthy.  This means that I really don't have anything salty around when my salt craving kicks in.  Therefore, it never gets satisfied and the craving continues on, and on, and on...  Maybe I should just cave in and buy something extra salty.  Or, is this my body saying "you need more salt."  I'm not really sure, or how I would find out.  Is there a "salt test"?

The cheese craving is better than the salt, because I actually buy cheese to put on vegetables.  However, instead of the normal amount I have been putting on extra just to satisfy the craving.  But, then the craving goes away...until the following day post-run. 

I don't really know if this is normal or not, but it is what is happening.  Training is all about learning, and that I have done a lot of recently.

Do you get cravings during your training sessions?  What food was it for?