Why Does Your Weight Fluctuate? - Your Definitive Guide to Reduce Scale Stress

If you have ever tried to lose weight, you would know about the annoying feeling that runs through you when you see the scale jump around like a Kangaroo across the Australian bush.

Sometimes it may even feel like you take one step forward only for the scale number to bring you two steps back. Rinse and repeat. This is only made worse when you find yourself plateauing too. 

Well let me assure you that the weight fluctuating is perfectly normal and a part of the process - which is easier said then embraced, I know. However, if you are to truly succeed in your weight loss journey you will need to embrace the good with the bad and be one patient son of a gun. 

That brings me to the purpose of this blog post you are reading right now as I type the word “WELCOME”. This post is about the ‘why’ behind the reality you may be experiencing with the scale weight fluctuating like a flux capacitor (greats scott!).

I am going to answer for you - Why does your weight fluctuate? (for reasons other than body fat change).

That way you can move past the frustration. Embrace the reality of it all. And start putting in energy where it matters so you can start getting better results while stressing less. 

The Scale Truth

Now the way I want you to use this blog post is as a guide to better understanding your body and gaining a greater appreciation of the physiology that occurs that you can’t control.

Why?
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Well, because I’m a firm believer in the mantra of:

Control what you can. Cope with what you can’t. And concentrate on what matters.

I call this The Control Paradigm and the stress you are experiencing with random, unexplained weight fluctuations can be managed using this mentality.

When you first accept that you can’t control the weight fluctuations that happen due to nature, you become empowered to focus on the solution and keep up the consistency needed to achieve your goal/s long-term. 

You could do everything by the book, and still the scale may go up 600g in one day.

You could have an “off day” and the next day your weight goes down 300g.

Sometimes it feels like there aren’t any rules to it all. And truthfully, in some ways, there aren’t any tried and true rules when human physiology is involved. That is why you need to focus on looking at trends in change versus only looking at individual daily changes.

That is why I recommend regular weighing where it is feasible and not detrimental to one’s mindset and mental health. This way you can assess the true changes going on and adjust your strategy with accuracy and using informed decisions instead of overreaction - which happens more often than you may think (perhaps even to you). 

Anyways, enough chit chat. Let’s delve into the meat of this blog post. The reason you clicked on this piece…to find out WHY DOES YOUR WEIGHT RANDOMLY FLUCTUATE?!

Ever feel like this looking at the scale?

Well without further ado, here are some of the reasons your weight may be fluctuating.
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Reason #1: Increased salt intake

One of the first places you need to look when trying to determine if your nutrition is causing your weight to jump up one day randomly is your sodium intake. The reason is that when we eat more salt, the body holds on to more fluids to balance out your levels and maintain control over your electrolytes (fancy word for ensuring the salt and other minerals in your blood are balanced). 

When you eat a consistent amount of salt in your diet, your body's fluid balance more or less balances out. However, it is when you suddenly increase salt intake one day (for example, let’s say a big fast-food feast at the end of a night out), that you notice a random spike in weight.

So ask yourself: have I had an extra salty meal recently?

If so, the weight fluctuation could very well be fluid retention - NOT fat gain. 

Reason #2: Increased carb intake

Carbohydrates can act as sponges in the body and therefore fluid retention may again be the explanation for your weight increase. See carbohydrates are stored in the body as glycogen - this is done in the liver and in the muscle. This is what allows for quick fuelling when you engage in some high-intensity activity as it acts as a ‘reserve tank’. 

So how does this relate to you? 

Well, if you had an extra carby day the day before then your weigh-in may be a lil higher due to the extra carbs in the system and therefore extra fluid retention. This is especially more pronounced when going from low carb to normal or high carb (for example, transitioning from keto to normal carb). 

Don’t believe me? Well here is some science for ya. Each gram of carb holds on to roughly 4g of water. You do the math. 

Reason #3: Change in meal timing

When you track your weight, there needs to be a minimal amount of variances and influencing factors as possible. You want to ideally weight yourself in the same state each day, at the same time, and in the same way. 

That is why meal timing can have an influence on the result. If you had a meal the night before later than you usually do then that can reflect on the scale - nothing to do with fat gain. 

This is especially true if it was a larger meal and ESPECIALLY if it was carb and salt heavy as I mentioned earlier. 

This, however, does not mean you need to stress over meal timing necessarily. I mean in an ideal world, having a set routine that you stick to is great but life isn’t always like that for most of us. Instead, simply understand you may need to account for this effect and look at the change over a period of time (e.g 2-4 weeks of weight scale change).

Reason #4: Elevated stress

Elevated stress levels lead to elevated cortisol levels. Elevated cortisol levels can both, directly and indirectly, influence weight - but in different ways. 

The first way is by making your body retain more fluids and therefore mask the true body fat changes that may or may not be going on. This would also present as sudden increases in weight from one day to another. 

The second way that stress can influence your weight is via directly leading to body fat gain by making you stress eat. This, however, is not the point of today’s blog as this is directly related to caloric balance and not relevant to non-fat weight fluctuations. 

Reason #5: Post-training adaptations

Fun fact: exercise can influence daily weight fluctuations. 

How? 

Well, the muscle acts as a sponge for nutrients, water, and glycogen for recovery. After a heavy weights session, for example, you will potentially be slightly up the next day due to the body holding on to more “things”. 

This is normal physiology. Don’t fight this. Embrace it. 

And as a side note: if you are exercising excessively then this causes stress which in turn can lead to fluid retention as mentioned previously. However, this is generally nothing to worry about and is a natural occurrence. Just keep on keeping on and stay consistent, young grasshopper!

Reason #6: Menstrual cycle 

It is perfectly normal to expect some increase in weight at the start of your menstrual cycle. This will generally go away after a few days so don’t stress about it. The reason for these fluctuations are namely due to the hormonal fluctuations that occur. 

I see this so often with the many female clients I work with. I help them to understand that they need to be resilient during this and not let it affect their mental state or make them quit on their nutrition plan. Doing so, can and often will lead to actual body fat gain. 

This is why keeping a regular weight log can be an effective way to assess trends and truly understand what is going on in your body.

Of course, only focusing on the scale for progress is a big NO NO for me so don’t do that and instead look at ways to complement the scale and see true results and really determine your level of success.

Reason #7: You haven’t pooped yet

And finally, one of the main reasons you may notice the scale is higher today than yesterday is that you simply haven’t gone to the bathroom yet.

The difference can be small or more significant and if you eat a lot of fibre then the change can be even more pronounced. 

So where possible, go to the bathroom for both number 1 and number 2 before your weigh in. 

Simple.

An example of a years worth of weight data showing the extent of fluctuations.

So what now?

As you can see, there are a number of different reasons your weight may fluctuate irrespective of how adherent you are to your plan. And a lot of the time it has nothing to do with body-fat. 

So please stop stressing over the day to day ebs and flows of the weight scale. Start looking beyond the scale and assessing your progress through a more “holistic” lens and accounting for natural fluctuations that occur. 

However, sometimes the reason for the weight not doing what you want it too could very well be due to your nutrition and exercise plan not being adhered to or not being correctly calibrated yet and in those occasions, it’s a good idea to adjust or get a second pair of eyes on it to help break you through it. 

How can you know?

Well, the best place to start is to ensure you start looking at trends of change over time as well as using more than just the scale to determine progress (or lack thereof). 

I guess you could say it starts with true awareness of the situation over time. Correct awareness does precede change after all. 

I hope this post has helped give you more clarity around the reasons for your weight scale showing you things you don’t want to see. Hope it now eases your mind a bit and reduces your stress (which in turn may actually help you as I mentioned earlier that stress is a contributor).

Now of course, if you have read all of this and you are still feeling like you need help and want to feel less overwhelmed while getting the results needed to achieve your goal and…

If you want my help getting objective outside eyes on your nutrition and goals… overcoming your obstacles and helping you achieve results faster… 

I’ve recently opened up spots in my 1-on-1 coaching program. 

If you’re an athlete or weekend warrior already hard at work on your health and nutrition journey and you want my help scaling your results while stressing less (and less guesswork)… 

Just send me an email to aleksa@theclimbingdietitian.com.au and tell me a little bit more about yourself and your current goals and obstacles...

If I think you’re qualified for the program, I’ll respond with the next steps.

Talk soon.

Aleksa
Sports Dietitian and Nutrition Coach