What My Grandma Always Told Me

My paternal grandmother, who passed away nine years ago as a result of a sudden stroke, was a health nut. She and my grandfather, I believe, lived a longer and healthier lifestyle because of their diet and exercise regime. Grandma loved Prevention magazine, and was always following up with us, copying articles and sending them in greeting cards. One particular article she mailed to me while I was in college stuck in my mind and has definitely affected the way I consume beverages.

Apparently, as early as the late 80s, there had been discovered a link between phosphoric acid and poor calcium absorption. This was of particular interest to my grandmother, because her daughter, my Aunt, was a big Diet Coke drinker. Granny was always on Auntie to stop consuming the stuff, at least, in such large quantities. Here is a nice article from Harvard on the subject.

And now, almost two decades later, I'm walking through the grocery store and see a little blurb on the side of a Diet Coke twelve-pack about how Diet Coke is a good source of hydration. They've even got an entire website dedicated to their products and how wonderfully hydrating all of them are. Yet I'm still scratching my head about the Diet Coke, because isn't caffeine a diuretic?

So I decided to do a little research on that. According to the nutrition advisor at physsportmed.com:

Caffeine also has a diuretic effect—that is, it enhances urine formation, often causing a need to urinate within an hour after consumption. Yet two studies with subjects who took caffeine before they exercised (1,2) showed no detrimental effects on hydration during exercise. Thus it appears that caffeine does not increase urine production during exercise. The extra adrenaline your body secretes during exercise may block caffeine's effect on the kidneys (3). However, responses to caffeine vary, so you should base your preexercise consumption on how caffeine affects your body.

After exercise, caffeine is a poor choice for fluid replacement. The safest bet is to tank up on noncaffeineated beverages just after activity, and then later, if you so desire, enjoy your favorite caffeinated beverage in moderation.

So, if Diet Coke might be okay while you're working out, but is overall a shitty choice for overall hydration afterwards, is it really fair or accurate for the Coca-Cola Company to be pushing the hydration thing on all of their beverages? I think not.

And it would piss my Grandma right off, may she rest in peace, that they're trying to make it appear as a healthful choice, in general. Assholes.