I’m currently monitoring my weight, and more importantly my fat percentage, to see how quickly a low fat diet has an effect – blog post on that to come later.

As part of weighing myself every week I wondered how much variation there was in the figures and therefore could I really tell if I’d had a good or bad week?

So as a little mini-experiment I weighed myself every hour or so throughout one day to see how much the measurements fluctuated – and here’s the graphs.

You can see that my weight rises throughout the day with spikes after lunch and dinner, and conversely my fat percentage drops throughout the day – with corresponding troughs after meals.

Which seems to make sense to me - eating a good meal doesn’t immediately convert it into fat and so the fat percentage is temporarily lowered – but you’re back where you started the next morning.

Results

Throughout the day, although it was random variations, my weight varied plus or minus 0.5kg (+/- 0.4% fat). And I guess this amount of variation should be no surprise as even a small glass of water weighs 0.1kg.

So for anybody watching their weight anything less than this shouldn’t be considered a success – as Peter Kay famously said in his stand-up routine on Slimming World – “I shit a pound!”

Scales Accuracy

I also did a micro-experiment within the mini experiment as I wanted to see how much the fluctuations were due to the accuracy of the bathroom scales (OMRON BF508 Body Composition Monitor).

Taking 3 measurements immediately after each other, and without moving the scales in case floor position has an effect, they showed a variation of +/- 0.1kg (+/- 0.2% fat) which seems as good as you’re going to get for a consumer product.