(This is part 1 of my series Should you weigh yourself daily or weekly? Part 2 is here.)
Assuming that you’re working on managing your weight—either trying to lose weight, or trying to maintain the same weight—how often should you weigh yourself?
There’s mountains of misinformation out there, telling you that at the very most, you should weigh yourself once a week. Many doctors still give this advice, and Weight Watchers and most other weight loss companies say the same.
But it’s not true. The research studies—showing that weighing yourself more often is closely linked to weigh loss—are accumulating. I’ll have a blog post on these soon.
And most of the arguments against weighing yourself daily are easy to debunk. I do that in my book Weigh Every Day. There’s a whole section entitled “Why not just weigh yourself weekly?”
Here’s one of the reasons that you should weigh yourself daily instead of weekly.
Weight fluctuations cause more problems if you’re weighing yourself weekly
When I say fluctuations, I mean those changes in your weight that seem random. These are changes caused by things like water retention, not having had a bowel movement in a few days, etc. I’m not talking about weight changes that are caused by eating too much.
Here’s what some people say:
Weigh yourself once a week, after you wake up every Monday morning. This eliminates things like water retention and bowel movements, which can cause changes in your weight.
But how could weighing yourself once a week, instead of once a day, eliminate fluctuations in weight? Do the random fluctuations somehow disappear on the one day of the week that you weigh yourself?
No, they don’t disappear. The meaningless fluctuations are still there. In statistics, these fluctuations are sometimes called “noise.” They’re what we want to ignore. The real data—weight changes caused by fat loss—is what we’d like to track, but the noise can be confusing.
The mistake that some people make is thinking that taking fewer measurements—weighing yourself once a week instead of daily—means that there is less noise. But that’s not what happens. There’s the same amount of noise, but since you have fewer measurements, it’s harder to see real changes.
With 7 numbers, you have a good idea of how your weight has gone up and down over a week. But if you have just one number, you have no sense of what normal ups and downs look like. And what if you happen to weigh yourself on a day when your weight is higher? You’re more likely to get discouraged. If you have the numbers for every day of the week, to balance things out, it’ll be easier to see the overall trend.
Here’s another example. What if you wanted to get the average temperature for July? Would it be more accurate to take the temperature reading every single day in that month? Or would it be more accurate to measure it once a week?
Of course, you’ll get a much more accurate number if you measure the temperature every day. If you only did it once a week, you could easily hit a few hotter days, and be far off from the true average.
