Weight Measurement

For the best data over the long term, try to weigh under similar conditions every time you weigh. Many people, myself included, weigh each morning when I get up after I pee and before I eat anything. This is about as similar condition as I can expect; however, there's still a LOT of daily fluctuation. Three days ago about 2.5 pounds up in one day, then no change, then about 2.5 pounds down the next day.

That's a lot of noise in the data. If you only weigh yourself once a week, you might assume you gained or lost a few pounds depending where you are the day you weigh. So some people who weigh weekly also pick a day that can be as similar to other weeks as possible. It's still probably ideal to weigh first thing in the morning.

Another thing I do is use a weight TREND to help eliminate some of the noise. I actually use several. One is a ten-day rolling average that automatically calculates in the spreadsheet where I keep my daily weights. Another is TrendWeight. It uses a different algorithm and gives some graphics I like. You can zoom in or out to one week, two weeks, four weeks, three months.... It also gives you an estimate of your loss/gain rate. If you look at a graph up to three months, your prediction is also displayed.

Here's an example of the output:

You can't enter your data there directly. If you have a Fitbit account that syncs to a device or scale, it will update automatically. I have to log in to a Fitbit account and enter my weight manually. It also gives some graphics, but I don't like them as well. I also use WeightGrapher. It uses a slightly different algorithm than TrendWeight, but it also has the option to show what your weight trend was a month ago.

For a good look into why using weight trends is important, see The Hacker's Diet, especially the section on Signal to Noise.

Many people also use body measurements in addition to weight scale. Sometimes you can see differences over time with a tape measure that the scale masks. Those measurements can change more slowly, but it's just another way you can assess your progress or maintenance.

I also weigh every morning after I go to the bathroom. My weight goes up and down a little, which is good for me to know. If I weighed once a week I'd worry about small fluctuations. Doing it daily, it's just noise. I look for new highs or new lows.