Why Does My Weight Yo Yo So Much - Personal Trainer Dublin

Why Does My Weight Yo Yo So Much

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“It’s totally normal that you haven’t lost anything for the last couple of weeks despite following the plan exactly. If you want slow sustainable and predictable weight loss, you shoulda been a dude” – that’s a conversation I have with ladies on the regular.

If you were born without a Y chromosome, you’re in for a bumpy weight loss journey. We see it all the time with the gals we train. You diet hard, follow the plan word for word, stay in at weekends, and train really hard 3-5x per week.

Each morning you jump on the scales hoping to FINALLY see a difference, only to have to step off defeated and deflated because the numbers are the exact same again (orrrrr maybe they’re even higher?).



It doesn’t matter that your clothes are fitting better, or that your energy, fitness and strength levels are all up. We promised you a change on the scales, and you haven’t seen it yet.

So what gives? Why do women experience such crazy weight fluctuations?

One of the ladies we train, Niamh asked me about it a while back, and I shot off a message that roughly said…

Welcome to the minefield that is trying to understand weight fluctuations. There’s about 1,000,000 reasons, give or take, why it can swing.

Heres a few;

– higher salt content in a meal can lead to water retention

– low water intake can lead to retention (counterintuitively)

– more water can lead to more bathroom trips and a lower weight

– eat later in the day, you’ll weigh more the next day cos there’s food sitting around that’s not digested and pooped out (and vice versa)

– some days high carb will lead to you being heavier the next day, some days it’ll lead to you being lower

– stress can effect whether weight moves up or down

– sleep can effect whether it’s up or down

– the training session and type of training may lead to some generalized inflammation in your body which means you’re heavier on scales

– cycle can effect weight DRASTICALLY

– how many layers you slept in and how warm you were during the night can mean more / less sweat which effects morning weight


….essentially everything can effect your weight and trying to pick one thing that drives day to day fluctuations is night on impossible, which is exactly why we focus on the weekly average weight as over time it tends to level out over time.

But not only are there a ton of reasons why you could be up or down on the scales, there’s a ton of different combinations within those reasons as to why you could see massive swings over the course of a few days.

For example, if you’d a stressful day in work, didn’t get a chance to drink much water, got a takeaway late at night at your desk and came home and shoveled in some chocolate, you’d probably expect to wake up a bit heavier on Friday morning.

Then, come Friday night you’re straight out the door after work with the girls, you’ve a couple of glasses (bottles) of wine, and a few G&Ts as you dance the night away. You’re good – so no trips to Charlies afterwards.

When you wake up on Saturday morning your weight will be WAY down. You’ve had no food in about 18 hours and are probably massively dehydrated.

There’s no way you can get a reliable read on your weight or use it to form any kind of estimate after a couple of days like that. And while I’m perhaps illustrating an extreme comparison there, hopefully you get my point.

For women especially, wild swings in weight during a diet or weight loss phase is normal. It sucks SO hard. But it’s normal. It’s why you can’t just judge your progress on how much you weigh. You HAVE to take into account all of the things you can’t account for (sorry… I know).

What can you do about it? Mechanistically, not a lot. You could make sure you’re drinking 1.5L of water for every 25kg of bodyweight if you want to force a bit of extra urination.

You could ensure to only eat lean white meat, green veg and white carbs (rice, potato etc) during the week to ease the digestive load.

You could track your fiber hard or go on some sort of juice cleanse.

But really none of those things will have any bearing on your long-term success.

If you pick a proven and tested plan that works over a 6-12 week time horizon, track your morning bodyweight after the bathroom each day, take progress pictures weekly and note how your clothes are fitting, and track energy and mood over the course of the training program, then you’re gonna do pretty damn well.

Some days have a higher number on the scales. Some days will have a lower number on the scales. But isn’t it great that that’s all it is – a number on a scales? Not any kind of determinant as to your value, worth or beauty?

I love the scales because it gives a valuable metric over time, but I hate it because it makes people who are working really hard and being successful feel like shit.

If I was in a relationship with the scales on Facebook, I’d say “it’s complicated”.

If you want a non-complicated relationship with a gym that’ll just give you the truth straight to your face and help you to navigate the muddy waters of the internet bullshit canal, I’d love you to come in and give us a go.

Take us up on an offer of 6 free transformation training sessions, 1 of which is your own private personal training session, and let us show you why we’ve 150+ 5* reviews on various social media platforms.

Grab your free session here now: https://revolutionfitness.ie/pt-intro

James Hanley

Strength Coach. Performance Specialist. Dog Lover. Powerlifter. And the guy behind the scenes in RevFit that keeps the plates spinning.