Why Does My Weight Fluctuate ? 5 Reasons Why

why does my weight fluctuate

The question of why does my weight fluctuate has probably come into your head a time or two before.

You step on the scale in the morning.

After you use the restroom, before you eat or drink anything, and fully naked of course because we don’t want any false readings.


Okay it clearly must be a mis read.

You move the scale around to get a better reading.

Matter of fact, you just take the batteries out and put new ones in for good measure. Don’t want to have an inaccurate reading is all.


*Scale goes through bathroom window*.

I am here to tell you you don’t have to freak out.

You did not gain body fat, that is physically impossible to gain 2 lbs of body fat overnight.

The scale is going to fluctuate everyday for the rest of your life for a plethora of different reasons.

None of which are going to hinder your long term progress.

So, you read to know the answers behind the question of why does my weight fluctuate? Let’s dive into some now.

Why Does My Weight Fluctuate ?

5 Reasons The Scale Will Fluctuate


When you include more sodium into your diet than you normally eat, you will retain water weight.

Let’s say all week you have eaten relatively low sodium.

You eat lean meats, veggies, some quality carbs like sweet potatoes or oatmeal.

You don’t eat out a ton and you cook everything from scratch at home, so you are able to control how much sodium goes into your food.

Then the weekend rolls around.

You head out to eat with your friends and family.

You may crush a few pieces of pizza, you might have some pasta with that incredible sauce you love, or maybe you have a steak and potatoes.

But all of those things are loaded with sodium because the sole purpose of restaurants is to have you enjoy the food so you come back again.

Not how much sodium is in their food.

So as opposed to your normal diet that is relatively low in sodium, you eat one or two meals that make greatly surpass your normal sodium limit in a day thus leading you to retain water weight.

This is not to say sodium is bad, because I do not believe it is at all. It can actually greatly increase workout performance by aiding in hydration.

But just know if you have a meal that is higher in sodium than what you normally consume, you are going to retain water weight.

Yet that is just it, it is water weight, NOT BODY FAT.

And as soon as you get back on track to your normal routine it will excrete itself, which your body is great at doing. Hence why “detox teas” or “full body detox cleanses” are a total scam and waste of money.

Anywho, moving right along, let’s get into the next point shall we?

High Carb Days

First off, no carbs do not make you fat.

The only way to store body fat on your body is by eating in a calorie surplus, aka eating more calories than what your body burns.

Okay sorry I had to say that to start us off here, now diving in.

When we eat carbohydrates our body breaks them down to the simple sugar call glycogen.

We use this glycogen as our main source of energy for our entire body, including the main source of fuel to the brain.

Glycogen gets stored in different places in the body, the ones most apparent to this conversation would be the liver and muscles cells.

Cool Science But.. What Does This Have To Do With Scale Fluctuations?

I know I know sorry, I nerd out on this stuff from time to time.

For every 1 gram of carb you eat it causes anywhere from 3-4g of water retention in your body.

There are roughly 454g of water in every 1lb.

Your liver holds about 100g of glycogen.

Your muscles cells hold anywhere from 400g-700g of glycogen. This is much more dependent on the persons current body fat, skeletal muscle mass, diet history, to name a few.

Okay.. but scale fluctuations..

Right right.

Let’s say you have a high carb day.

That extra water from the carbs is going to get stored as glycogen in your muscle cells, causing you to retain some water weight.

Yet again, this is okay and normal. No reason to freak out.

So next time you ask “Why does my weight fluctuate” but you just had a ton of carbs the night before.. now you know 😉 .


Sometimes you just gotta unclog the plumbing.

If you want proof that you can gain weight or lose weight simply losing the restroom, I urge you to head to my YouTube video I did on the difference between weight loss vs fat loss.

It is not uncommon for your weight to move between 1-4 lbs from simply using the restroom or not.

Strength Training

When people ask me the question of why does my weight fluctuate, they are usually blown away when they hear this one.

When you strength train you tear your muscle fibers apart.

This causes your body to start the inflammatory response to allow your muscle fibers to heal and recover.

During this inflammation process your body is going to

  • retain water weight
  • Increase swelling inside the body
  • Increase an uptake and retention of nutrients / water to the muscles

It is all apart of the adaptation process necessary to grow stronger and more defined muscles. This is a necessary and positive process going on inside your body.

In the short term, this will reflect on the scale by going up.

Yet again, this has absolutely nothing to do with your long term weight loss progress.

In fact, this actually is going to help you lose weight long term because through the process of building stronger muscles you are going to increase your metabolism.

The more lean muscle mass you have the higher your metabolism is.

The higher your metabolism is the more calories your body burns ( from doing literally nothing by the way, this is why strength training should be prioritized over cardio for weight loss).

The more calories your body burns, the more advantageous your weight loss journey will be.

Therefore keep lifting heavy yet just know the next time you get done an intense workout session the scale may read higher, and that is okay.

Time Of The Month ( Ladies Only)

If you are a female reading this you are already probably shaking your head yes.

Ladies when you go through that time of the month, you are normally going to retain some water weight.

During this time period there are two phases we are going to look at, the follicular and your luteal.

Let me give you the good news first.

During your follicular phase, you can actually get some kick ass workouts and be strong as heck.

This is when your testosterone is highest and you can be empowered.

So, that’s at least some good news during this time.

Now the news you knew was coming.

During the luteal phase, this is where we see a rise in progesterone and in estrogen levels.

During this phase you are going to have some increased water retention and bloating, which can lead the scale to read higher.

Again, that is totally normal and okay.

You are not gaining body fat you are simply just retaining some water weight.

I tell all of my female online coaching clients I work with that even though the scale may go up, as long as you continue to eat in your deficit, not only will your weight go back down, but it will dip lower than before due to you losing body fat.

So ladies don’t sweat it and thank you for keeping the human race alive. Guys, just be thankful, that’s all.


Before I dive into cortisol and stress let me make something abundantly clear.

A lot fitness marketers will try to sell you on the fact that if you are stressed out that is the reason you are gaining fat.

They will try to sell you their diet or workout program and make you believe that is there reason you cannot lose fat.

That is f*cking wrong.

Let me tell you this in regards to stress.

Stress does not inherently make you gain fat.

What makes you gain fat is what you decide to do once you get stressed.

You tend to eat more calories.

You tend to skip workouts.

Leading you to not be in a calorie deficit which is the only way to lose fat.

It is not inherently the stress or cortisol in your body, it is what actions you take once you get stressed that lead you to not be in a calorie deficit which leads you not to lose weight.

Whew, alright, now that I got that out of the way.

Let’s talk about what stress can do.

When cortisol (stress) is increased it can make you retain water weight temporarily.

This would make you weigh more on the scale.

Then when you get out of that stressed state, you normally flush all of that water weight out.

This is why when people reverse diet they sometimes lose weight.

This is because such a low calorie diet is a physical stress on your body.

If your body is stressed out we just saw it can, in the short term, hold onto water weight. When you reverse diet you add calories back into your diet.

This can relieve your body of some of the stress you were under, you flush out water weight, and the scale drops.

But not because you were “eating too little calories and going into starvation mode”, because that is not a real thing.

It is simply because your body was stressed out and once you added back in calories, cortisol dropped, water got flushed out, and you lost weight on the scale.

This is to note if you would have kept eating that low calorie amount you would have eventually lost weight, it would just be after the initial water weight retention from the cortisol dropped.

Why Does My Weight Fluctuate

Now that you have some of the answers to your question of “why does my weight fluctuate”, let’s talk about what you should and should not do when this happens to you.

What NOT To Do

Freak Out

When your weight spikes up you feel like you did something wrong so you have to correct it.

Listen to me very clearly.

You did not do anything wrong, and you do not have to do anything differently.

The scale fluctuating is a normal occurrence. It is going to happen.

This is not a time to panic nor a time to try and switch what you are doing.

This is a time to look outside of your emotional reaction to the scale going up and look at the logical reasoning behind why it may have gone up.

Did you have a meal higher in sodium?

Did you have more carbs than normal?

Did you just get done a heavy strength training day?

Are you super stressed out?

Look at things from a logical perspective as opposed to an emotional one, understand it is normal and that you did not do anything wrong, and keep going forward.

Over Restrict Yourself

I mentioned this above but when your weight goes up your automatic first thought is okay well I have to be more strict with myself.

I have to cut calories even more.

I have to stick to only salad and chicken.

No, no you don’t.

Remember this is all about long term progress.

Temporary weight fluctuations do not indicate or hinder your long term progress.

You do not have to eat less food the next time, rather continue sticking to your plan as consistently as possible.

Do Tons Of Cardio

This was probably your next thought.

“Okay well if I am holding water weight I am just going to go do tons of cardio, sweat a bunch, and the scale will go back down”.

How mentally healthy does that sound?

What does that make your relationship with exercise and the scale sound like?

Listen, it is all good.

Your body has everything it needs to excrete excess water weight. You do not need to go punish yourself by doing hours of cardio and sweating buckets.

It just is not worth it.

Simply get right back on track to what you have been doing that has worked well this entire time, remembering once again that short term weight fluctuations have no relevance to long term progress.

What To Do

So, what should you do next time you ask yourself why does weight my weight fluctuate?

Well you already did step one and that is to educate yourself.

Educate yourself on why the scale is going to fluctuate. Learn about why it is normal for it to do so. Understand that is has no relevance to your long term progress.

Beyond that, you simply keep going.

Do not let a few higher weigh ins derail you from your journey.

That would be like you running a marathon, tripping in the first 10 minutes, and quitting all together.

Your whole family is there cheering you on, you have all of this incredible journey in front of you, yet you quit after 10 minutes for one hiccup.

Don’t do that to yourself.

It is one thing to be upset about the scale going up. It is another to let that dictate your actions.

Keep doing what you are supposed to do even when it is difficult or you get challenged. That is how you create real change.

Then over time the more you work through these fluctuations you will realize the scale is just data.

One simple form of long term data to find out if what you are doing is working or not.

Key word there being long term.

This is a life long journey. The more you understand that the more you will enjoy it.

I truly hoped this article helped you. If so feel free to let me know below would love to hear from you.

Also feel free to share it with a friend or family member. As you probably well know the majority of people are looking for the answer to the question “why does my weight fluctuate”.

I wrote this article to provide people a scientific and reliable source they can learn from to understand what may be going on.

If you are interested in working with me, feel free to head HERE to fill out my coaching application form.

Look to hear from you soon.