You all know the routine: It’s 7:30 in the morning, your alarm clock is faithfully sounding off and the only thing you want is to go back to sleep. That’s not going to happen though, because as you lie there, you become increasingly more aware of the cries of your uncomfortably full bladder. Finally, unable to bear it any longer, you force yourself to get out of bed and briskly walk to the nearest bathroom.
What a wonderful way to start your day. But now you discover that you are also thirsty, almost unbearably so, and that the only thing on your mind at such an early hour is whether or not there is anything drinkable close at hand to make everything right as rain. So what does it mean to be thirsty?
As it turns out, a lot of it comes down to salt and how much you’re consuming in your diet. The more salt you’re taking in, the more that will be floating around in your circulatory system. This upsets the balance of electrolytes that your body likes to maintain and causes a mass dehydration of your cells as they shed water in order to compensate for that increased amount of salt in the bloodstream.
We won’t get into the details of how this all happens, but suffice it to say that your body enjoys being in a state of happy balance, or homeostasis, in most everything that it does. This includes fluid volume and what we in the world of medicine call your plasma osmolarity, which is basically just the measurement of how much stuff is in your blood. If at any point this delicate harmony is disturbed, water will shift from one place to another until peace is restored and business carries on as usual.
The issue arises when our frequent treks to Five Guys causes us to chronically consume too much salty goodness. With such a high salt load, the body compensates by triggering a thirst response more frequently throughout the day as well as by retaining more and more fluid in the kidneys to correct even the slightest deviations from the operating norm.
This is all well and good — until you run into situations when this water intake and conservation is insufficient in meeting the desires of the body to maintain homeostasis. At this point, the body will resort to other means to rid its world of extra salt, not least of which is an elevation of your blood pressure. Assuming that you are all young and healthy individuals, this will not be too much of an issue, but relevant to today is the simple fact that more salt in your diet means more thirst and water retention, and more water retention ultimately means more weight.
And just a little side note from a former Nalgene carrier to the rest of you out there: Please don’t think that sipping on more water throughout the day is making you any more hydrated than the rest of the world. Just like a salt bomb eventually sorts itself out in your body, a couple of liters of extra water that you drink just for the pure pleasure of drinking will ultimately find its way into the public sanitation system. If you’re not thirsty, chances are that the water will just go in one hole and out another.
Here’s the take home message: Substitute the fast food for a few more less salty, home-cooked meals this week, and listen to your body by only drinking if you’re thirsty. I think if you follow those two simple suggestions, you’ll find yourself a little leaner and maybe even more excited to strut that newfound beach bod this spring break!

David Sterns is a student at Georgetown University School of Medicine. ALMOST-DOCTOR DAVE appears every other Friday in the guide