Scale Fluctuations Are Annoying. Here’s What’s Going On

By Aadam | Last Updated: December 9th, 2020

On a scale of stubbing your toe and being punched in the face by Mike Tyson, scale weight fluctuations are probably a, hmmm, oh I dunno, sliced to a thousand pieces by a Samurai.

While that may seem highly hyperbolic, weight fluctuations on the scale can make or break someone’s day, week, and even diet. And for some people, it can feel exactly like that.

The problem, though, is your scale weight is a terrible metric for measuring your fat loss progress.

To explain why, we’re diving into the weird and highly annoying world of scale weight and fluctuations.

Understanding body ‘weight’

We can split your body into two distinct ‘parts’ – fat-free mass and fat mass.

  • Fat-free mass is everything that isn’t fat – muscle, bone, organs, muscles, water, etc.
  • Fat mass is, well, fat.

So when we talk about body weight, we’re talking about fat-free mass + fat mass. 

Gettit? Good.  

Now, let me ask you: what do you want to lose, fat mass or fat-free mass? Thought so.

Despite what the diet-world has led you to believe, nobody wants to lose weight, they want to lose fat.  

This distinction is important because, firstly: ‘weight loss’ is easy and can be easily manipulated, you see fighters (and powerlifters) do this all the time by extremely dehydrating themselves before a weigh-in; and secondly, having understood this you’ll better understand why your scale weight is a terrible metric to base your progress on. 

On that note…

What we talk about when we talk about scale weight

This is you.

Imagine for a second we cloned you and your clone is an android.

You both–Real You and Android You–weigh a certain amount. But this is where things begin to differ.

  • Android You isn’t a biological being, it’s a machine, it’s going to stay the same weight forever.
  • Real You, on the other hand, is a human being. Your body is far more complex than of your android twin and your weight will fluctuate hour to hour, day to day, and week to week due to several factors. Aa

When we talk about scale weight we’re talking about your ‘actual weight’ plus all the ‘weight anomalies’.

Actual weight + weight anomalies = scale weight

It’s these weight anomalies that cause the fluctuations that screw with your head. This is why, where your android twin will stay the same weight forever, you can see your weight fluctuate anywhere from 2-10+lbs within the space of a day.

So, what are these weight anomalies?

  • Carbohydrate intake: The number of carbs you’re consuming will affect scale weight. Remember, 1 gram of carbohydrate comes along with 3g of water. This is why when people go on a low-carb, or ketogenic diet, they see rapid weight loss (not fat loss) initially as the body drops water. Inversely, if you’re ending a period of low-carb or ketogenic dieting, you can expect your weight on the scale to go up.
  • Water retention: I wrote about this in detail here.
  • Menstrual Cycle: Ladies, your monthly cycle will make you retain water. I know, it sucks, but you’re awesome so smile. I wrote about dealing with the problem here. 
  • Stress levels: Increased stress = water retention and with water retention comes a spike in scale weight. 
  • Sleep: Poor sleep can also increase stress levels = water retention = weight increase on the scale. 
  • Timing of last meal: If you generally eat your last meal at 8pm, then one day you eat your last meal at 11pm. This will see the scale increase the next day.
  • The time you weigh-in: If you regularly weigh in at 5am and then one day weigh in at 8am, this will impact scale weight.
  • Alcohol consumption: Alcohol can dehydrate you, leaving you lighter the next day. However, alcohol can also increase hunger. So if you go out and drink and consume foods high in salt and carbs, this will also impact your weight the next day.

How these weight anomalies affect your scale weight

Here’s a hypothetical look at how all of this can affect your weight on the scale. 

It’s Monday. And the first day of your diet. You step on the scale to weigh yourself, and after a bit of number shuffling the machine spits out a number: 160 lbs. 

On Tuesday you do the same thing, and the machine spits out the same weight: 160 lbs. However, Tuesday was a really stressful day at work and due to work stress, you didn’t sleep properly. As stress levels increase, cortisol increases and some water retention occurs. 

On Wednesday, you step on the scale: 167 lbs. “What?”, you mutter as you scowl at the scale. “But, I’ve been sticking to my diet (calorie deficit) and exercising–WHY AM I GAINING WEIGHT?” Whatever. You put it behind you. You’re annoyed, but today’s the last day of the stressful project you’d been working on so that cheers you up a bit. 

As Wednesday comes to an end, with the deadline met and the project finished, you go out to celebrate with work colleagues. You drink, eat–but keep it controlled–and have fun. You’re so exhausted when you get home you fall straight to sleep. 

Thursday, you wake up feeling well-rested and energetic. You look over at the scale, dubious. But you step on it and weigh yourself. 159lbs. “WHOA. What the shit? I just lost 8lbs.” Elated, you get ready for work. 

Thursday is an easy day. A few emails and conference calls. You leave work early and meet up with your significant other and go for dinner. You get back home and it’s 11pm. You’re feeling a bit peckish, and seeing you have some calories remaining for the day, you decide to make a small snack. 

Friday. You weigh yourself. 161lbs. You’re annoyed because you think you gained weight, but you fail to realise that normally you have your last meal around 8pm. Last night, dinner finished at 9pm, and then you had the small snack at 11pm. This is what caused the fluctuation. 

You look over at the mirror and to your surprise, you’re actually looking leaner. “Hmm”, you say, “I’m pretty sure my abs weren’t that defined before”. “But I can’t be leaner, surely, the scale is showing I gained weight.” You sigh and get ready for work, taking one last look at your new definition as a smile crosses your lips. 

Later on Friday, you remember you totally forgot it was that guy-from-work-who-you-don’t-really care-about’s birthday today and he invited a bunch of you guys out.

It slipped your mind and you weren’t able to factor the occasion into your calorie totals. “I’m totally blowing my diet today”, you think as you stare at the numbers on MyFitnessPal. Friday night, you go out, and you totally do blow your diet. You drink and eat a bunch of high-carb, salty foods. 

Saturday. Your head hurts as you come to, a reminder of last night’s revelry. You look in the mirror and you’re looking ‘watery’ and ‘soft’. You stare at your reflection, disappointed, and then tentatively step onto the scale. 


“172 lbs!” You’re pissed off. Convinced you ruined your diet and progress you grudgingly step off the scale. 

You’re not feeling too hungry today. So you just eat to hunger. You also hit the gym; a strength-focused upper body session and a bit of light cardio at the end. Still not fully recovered from the night before, you go to bed earlier than usual. 

Sunday. You wake up and look at your clock: 11am. You slept for 14 hours. You’re feeling a lot better today and the long sleep was needed. You get out of bed and, though you’re afraid of what you’ll see, you look in the mirror: “WHOA”, you think. You’re looking infinitely leaner than you ever have. You’re convinced you dropped fat as your abs appear to be ‘popping’. You step on the scale. 159lbs.

Though you’re ecstatic, you’re also confused. “What the hell is going on?” you ask yourself as you flex in the mirror. 

The hell that’s going on is this

Due to the myriad of weight anomalies I listed above and illustrated in the story, your weight will fluctuate. Like so.

But these are perfectly normal, and even expected during a diet. As long as you’re eating in a calorie deficit, fat loss will still be occurring.

This is why I advise everyone to not get too caught up with the scale weight because it’s only one tool to measure progress.

In fact, sometimes I simply stop my clients from weighing themselves altogether because it messes with their head, which only stresses them out further, increases cortisol, that in turn increases water retention and sets forth an insidious cycle where I keep telling them to chill and they keep sending me 30-page emails expressing their disdain.  

Instead, focus on body measurements, progress photos, and performance in the gym (strength gains) because they are far more reliable metrics to gauge trends in body composition and your progress. (Read more about tracking progress in detail here)