The Scale Lies! Daily Water Fluctuations

December 22nd, 2009 by

I find myself addressing this very issue repeatedly in correspondence with clients, so I thought I’d just put my thoughts in one place.

When I say the scale lies, you probably say something like, “I agree.” However, do you really? If you do agree, then whatever number pops up on the Random Number Generator will have little to no effect on you, or how you feel right? If you don’t agree, whatever number pops up relative to the last time you checked will either have you singing for the day or moaning doom and gloom.

Now, I won’t go off on a tangential rant about the scale here a I’ve already done that in my Beware! Rant About The Scale post from a ways back. But I do want to post, what seems obvious I know, a simple reminder.

The scale is information. That’s it. What does it tell you? It tells you what you weigh that moment you step on it. That’s it. It tells you nothing else. It doesn’t tell you anything about the composition of your weight. It doesn’t tell you if you’ve lost fat, gained muscle, or if simply your body’s water balance has fluctuated. It just gives you information, and most importantly, information without any context, is useless.

Doing an honest assessment, I think most of us, when we’re dieting for fat loss are after a ‘look, more than we’re after a weight. The problem is that we tend to associate a look with a given weight, and this isn’t necessarily the case. I can’t even count how many people I know who’ve found themselves smaller than they were in times past (based on clothing sizes), yet are heavier. If you focused solely on the scale, well, this is bad news right? However, clearly if clothes fit better, you’re smaller, you’re leaner, you’ve lost fat. And if you’re all these things AND heavier? You’re fortunate enough to be carrying some new muscle. Don’t complain!

With my clients I have them check in officially at two-week intervals. As part of that check in, they submit their bodyweight that day as well as a number of girth measurements. Now, here’s my point today …

More importantly than the fact the scale doesn’t give you any information on what is happening with your fat and muscle which are slower changes, it also doesn’t tell you anything about day-to-day fluctuations in body water.

It could just so happen that you caught yourself on a ‘high’ day in terms of body water. If you did a little experiment on yourself you could see this in action. If it were not true, you’d basically weigh the exact same every day and any change would be a slow decrease. There’d be no upward blips ever. Weigh yourself daily for two weeks and watch how untrue this is. You’ll see weight fluctuating up and down by a few pounds over the course of the two weeks. Of course, over time the trend should be downward.

Now I tend to not recommend weighing very often because I think people are too obsessed and affected by the results of the stepping on the scale. So, my goal is to break this over time – again because as mentioned earlier, the scale is just information and information without context is useless.

However, in some cases I’ll ask people to weigh themselves daily and submit those numbers to me as well at the end of two weeks. Why? Mostly so that they can see what’s happening and see that bodyweight fluctuates a lot. What if on the biweekly day a person’s weight was 150lbs. And let’s say two weeks ago it was 150.5lbs. You might think, “Meh, only 1/2 a pound lost”. But how do you know that person didn’t weight 148 the day before? Very possible. They just happened to catch themselves on the high day.

Daily weight fluctuations are normal. They are not indicators or success of failure. Changes in sodium status, how much water you’re drinking (low water intake promotes water retention), hormonal changes associated with menstruation, glycogen status, etc., all affect bodyweight.

My point is simply to not put too much stock into what the scale says TODAY. It probably said something different yesterday and will say something different again tomorrow. Worry about what you’re doing – sound nutrition, training, and cardio. From there over time your bodyweight will take care of itself.

If you want, experiment with daily weigh ins for yourself so you can see this in action. If you’re a client of mine, I especially want you to keep this in mind. Focus on trends, not absolute numbers.