jd,

Really good response from Asaxy above, not too much I can add. Would like to say though, one of the big keys is to plan what you're going to eat ahead of time. Meaning, when you wake up in the morning you should already have your entire meal plan for the day (this includes snacks, soda pop, etc) planned out. Included in this plan needs to be the calorie count for everything you're going to be eating, as well as a ballpark figure of your sodium. While this may sound like a big nag at first it actually only takes a few minutes to plan out the day before, and so long as you're keeping track of what your intake is, then you will find ways to meet your targets. Be sure to throw in a day or two each week where you cheat and get a greaseball burger though!

Keep in mind that sodium isn't necessarily evil, the ideal amount for your body is not the same as everyone else- it depends on your activity level, metabolism, body chemistry, etc. For example, before I go on a long run I load up on carbs the night before (or morning if I've got a couple hours before the run) lotsa bread and pasta- typically between the sauce and noodles there's plenty of sodium in it. If I weren't going to be running 13 miles this would be a bad thing, but my body will thank me for it when I'm 7 miles into the run with 6 to go. An hour or so before the run I'll also load up on gatorade, which is also full of sodium. Once again, if I weren't going to be exerting myself this would be a bad thing. But because I'm loaded up on sodium and other electrolytes I can do the run in good time with no worries about muscle cramps, exhaustion, dehydration etc.