Dealing with Scale Weight Fluctuations

Daily changes in scale weight are completely normal and to be expected, even if you’re not trying to lose weight. I’ve seen my own weight bounce around 3-5 lbs within the same day, and it depends on a lot of things: how much sleep I’ve gotten, how stressed out I am, if I currently have food in my gut (both digested and undigested), if I’ve had water recently, or if I had any major changes in my salt or carb intake from the day before.  There are a LOT of variables at play!

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Many people step on the scale in the morning and immediately get upset if they see that they've gained weight. 😩 However, it doesn't always translate to body fat gain. • Carb intake, sodium intake, sleep, hormones, and even a hard leg workout the day before can all influence water retention and cause you to hold onto several extra pounds of water weight. Maybe you really, really have to go to the bathroom. Or if you've been eating in a calorie surplus and getting stronger in the gym, it could be that you've gained some muscle – and that's made up of mass, which means it can change the scale reading! • Be sure to consider ALL of these factors when interpreting scale weight, and remember that waist circumference measurement is typically a better indicator of body fat gain or loss than scale weight alone. • Weight gain does not always mean fat gain!

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The daily differences in weight don’t matter, the overall trend does, and that takes a few weeks to really ‘show’ itself.

Case in point?  My own Fitbit Aria data over a span of 3 months.


Start (Dec): 131 lbs, Current (March): 118 lbs

And just to show that it’s fat loss and not overall weight loss with sacrificed muscle:

Start (Dec): 26% body fat, Current (March): 18%

FYI: I use the body fat percentage calculated as a relative number, not an absolute number, as the impedance method of measuring body fat is highly dependent on how hydrated you are and have a fairly wide margin of error.

There are lots of spikes upwards and downwards from day to day, but when you take a holistic view at both graphs, you’ll see that the general trend is downwards.

I compulsively hoard data because I’m a scientist at heart.  I treat my body like an experiment and I see what causes my weight to bump up – and consequently, I don’t worry about it.  When I know I’ve had more carbs or a saltier snack than usual the day before, I expect the weight to bump up a few pounds, and I don’t worry about it.

If you still want to weigh daily, weigh yourself on the same scale, in the same place, at the same time of day.  I could see how seeing daily weights and measures might trigger some compulsive behaviors, and if you have a tendency to do this, just ditch the scale entirely and go with how your clothes fit and how you look in photos.  Progress photos and bust/waist/hip measurements are so helpful for keeping an objective eye on things!  Whenever I feel discouraged at my progress, I put my starting photo and current photo side to side to get myself out of my own head.  It sounds silly, but it really does help me realize that I haven’t been spinning my wheels for weeks on end.

All in all, don’t fixate too much on the numbers.  Measuring weight is supposed to be a useful tool, not an endpoint in itself.  For example, aiming for a lb of week of weight loss might be setting yourself up for failure, as you’re relying on a measure that’s highly subjective to even the smallest changes.

What I would also like to point out is how long this fat loss took.  It’s also not a perfectly straight downward trend line – I had a bit of a stall in late January where the trend line flattens for a bit.  Fat loss can be a slow and demoralizing process – but there are ways to do it sustainably, in a way that doesn’t lead to yo-yo dieting/binging and purging.  Losing fat shouldn’t come at the expense of your long term health, both physical and mental.

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