Tracking losing weight

Chris Northwood
2 min readJun 17, 2017

I’ve mentioned to a few people the approach I take to tracking losing weight, because it’s sometimes a bit different to the fairly blunt you should weigh in daily/weekly/never weigh in advice that seem to be predominant.

The approach I’ve been taking is to weigh in daily (at the same time every morning, first thing in my morning routine), but then to track a moving average of the last 7 days. I generally like this approach, as you sample more frequently, but by focussing on the moving average, you avoid any day-to-day fluctuations, which gives you a nice smooth progression.

I use a Fitbit Aria scale, which also measures my body fat percentage, so I track that too (ultimately this is the main thing I care about, as I’d like to lose body fat specifically, rather than just weight). The Fitbit Aria has wi-fi, which means I can get the data out of it fairly easily. I originally tried to use IFTTT to automatically log it into a spreadsheet, but the IFTTT integration doesn’t log body fat percentage, which is a bit of a shame. I instead use Fitbit’s data exports to get the data out and then copy and paste it into my Google Sheet.

As Medium still does not support alt-text, for any screen reading users, the image above is a screenshot of my Google Sheet. The date, weight, BMI and fat columns come from Fitbit, but the others are all computed. I take a moving average of all of those factors, and the compare those averages to the previous week’s and month’s value to determine my progress! I highlight the last day of the week and month to get myself a headline figure, and then also highlight my daily weight/fat to see if it’s lower than my moving average (to help me determine if my daily weigh-in is on trend). I also colourise BMI, because even though it’s not a good measure for an individual, it’s nice to know I’m no longer “obese” (and merely overweight).

The main downside of this approach is that the moving averages become less accurate when I miss a weigh in (usually when I’m not at home). Fitbit’s data exports will fill in any missing days by extrapolating between two weigh ins, but this does lose accuracy.

I know this solution is bespoke to me, but for anyone else who’s trying to lose weight, I hope it inspires you to track your weight in a similar way!

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Chris Northwood

A technologist wanting to share knowledge and iterate towards a better world.