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What I learned trying to drink a gallon of water a day

I am as much of a sucker for an atttention-grabbing headline on the internet as the next guy – even more so if it involves health and fitness. So when a story about drinking a gallon of water a day popped up, I had to learn more. (And share on Facebook, of course, and throw down the challenge: a gallon of water a day for a month!)

So here’s what I learned while attempting to drink a gallon of water a day.

First lesson: I’m really bad at weights and measures. On the first day, I thought I had reached my goal fairly easily by finishing four 16-oz. glasses of water, until my beloved husband pointed out that that is only a half-gallon. Yikes! A gallon is indeed 128 oz., and that’s a freakin’ lot of water.

Second lesson: I wasn’t even drinking as much as I thought I was before I started the challenge. While that 64 oz. seemed pretty do-able, I was really only ingesting about 50 oz. each day. I was better at it when I was not as busy; spending more time at my computer somehow made it easier to take regular sips of water (maybe to break up the monotony). The busier and more active I was – running errands, working with clients and teaching my group classes – the less I managed to drink, just the opposite of what I should be doing.

I put rubber bands around my water bottle to track the number I had finished during the day. I tried different kinds of bottles and glasses, to find the one most conducive to reaching my goal.

I only intermittently reached my goal of a gallon a day, and I certainly didn’t do it consistently for a month. So I never experienced the significant changes described by the author of the original story, although I was probably drinking more at the start than they were. But I wanted to know: how much water should I be drinking, anyway? So I checked some resources to find out.

My rule of thumb has always been to drink a number of ounces equal to half of one’s body weight in pounds. For example, a 130 lb. person should drink 65 oz. of water. This just happens to be the recommendation of Tiffany Chag, a nutritionist at Tom Brady’s TB12 Center with a master’s degree in nutrition and exercise physiology from Columbia University. If it’s good enough for TB12, it’s good enough for me! (It should be noted that Brady is said to drink much more than that, but hey – he’s Tom Brady, and I’m not!)

There are various ways to estimate your fluid intake needs, from simple to complex. According to my experts at Precision Nutrition, fluid intake can be calculated as:

  • 80 – 110 mL of water per 100 kcal of metabolic rate (BMR) (OK, so we’ve already determined that I’m bad at weights and measures, and now I have to calculate my BMR? Sure, I’ve got the capacity to do it, and if you geek out on this kind of stuff, have at it. In the meantime, what else you got?)

  • 30 – 40 mL of water per 1kg of body weight (This ties in very closely to my ounces-to-body weight calculation, and with a little help from Google I can convert mL to ounces and kg to lbs.!)

A generally safe recommendation is 3L (12C) of fluid per day; approximately 1L (4C) will come from food, with the balance (+/- 2L, or 8C) from fluid ingestion, i.e. drinking.

What about other drinks? Does it matter what you drink? Any beverage or fluid-rich food will keep you hydrated, but it’s best to stick to calorie-free beverages like water and unsweetened tea or coffee. (Yes, caffeinated beverages count! Learn more about hydration myths here.)

Don’t like plain water? Flavor it with natural juice from whole fruits like lemons or limes, or infuse it with other fruits, veggies or herbs. Avoid packaged flavorings or drink mixes; remember to always read labels, and stick to minimally processed or whole foods as much as possible.

It’s still a goal of mine to increase my water intake every day; I’m shooting for 80 – 100 oz. a day. Like all new habits, I’m focusing on making small, incremental changes, because they add up.

Learn More:

Read the article that started it all here:

Read the interview with Tiffany Chag here:

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