Your body is more chemistry set than calculator. Here’s why the scales move daily — and why you shouldn’t stress about it.
I recently came back from a holiday in a very sunny Ibiza – and it was great; a little different from when I went in 1996, but that's another story. I worked really hard on my 'holiday body' and was very proud of where I got to: I departed the UK at just over 81kg and returned some ten days later just shy of 84kg. A couple of extra kilos, a slightly tighter waistband, and a head full of good memories. All worth it.
Back home to the normality of the day-to-day, I did what most people do: slipped back into my calorie-deficit plan, added some cardio, and tried to shake off those “holiday pounds.” Easy, right? Except the scales had other ideas. A week back having shaken off a kilo and a half, I fell off the wagon over the weekend and imbibed more food and drink than I should have (difficult to focus during holiday blues I guess and was all-too easily led astray) and naturally I knew I’d put on weight.
On the Monday, scales tipped at just over 84kg: fair enough I suppose. The next day, having gotten back into my regime, I weighed in at 84.5kg….wait, I’ve gained weight??? Then, two hours later, after a weights session, I stepped on the scales again, more out of curiosity than anything else: 84.1kg.
That's a “loss” of nearly half a kilo in the time it takes to train. Magic? I wish, but sadly not. And here’s the interesting part: sometimes you eat and drink your way through a weekend and barely gain anything. Other times you’re clean as a whistle — tracking your food, watching those macros and drinking water — and the scales go up. So, what’s really going on?
Fat Gain vs. Scale Weight
First thing to know: fat doesn’t appear overnight. To put on a kilo of fat, you’d need to eat around 7,000 calories more than your body actually needs. That’s a heroic effort, even on holiday. But your scale weight? Well, that can swing daily. It’s not just fat; it’s water, food, hormones, salt, carbs, alcohol, even how much sleep you’ve had.
Think of the scale like the weather in Britain: up and down, sometimes for no obvious reason, and occasionally sunny just to confuse you.
Why the Scale Bounces
There’s a number of reasons that that needle or those numbers will fluctuate. Here’s a few:
Water Retention: Salty tapas, pizza, a few cocktails — your body holds water to balance things out. You feel puffy, but it’s not fat.
Glycogen (Carb Storage): Muscles store carbs as glycogen, and with every gram of glycogen comes 3–4 grams of water. That’s why a carb-heavy weekend can add 1–2kg on the scales, even if your body fat hasn’t changed.
Alcohol’s Odd Tricks: Alcohol dehydrates you short term (ever noticed you’re lighter the next morning?). But give it a day or two and your body rebounds, holding more water than before. That explains the “mystery weight” after a weekend of drinks.
Food Volume & Timing: Weigh before breakfast vs. after dinner and you’re also weighing the food still in your system. That 400g I “lost” in two hours? Mostly sweat, water, and the fact my breakfast had digested a bit.
Sleep & Stress: Too little sleep or high stress boosts cortisol, a hormone that makes you retain water. One bad night can add half a kilo to the scale.
So, Just How Much Can You Swing in a Day?
It’s completely normal to move 1–3kg in 24 hours. In some cases (travel, alcohol, salty meals), even more. And almost all of it is water, glycogen, and digestion — not fat.
Should You Worry?
The short answer? No. Daily weigh-ins can be useful, but only if you zoom out and look at the weekly average. Don’t panic if Monday looks higher than Friday. That’s just your body chemistry doing its thing. Fat gain and fat loss happen slowly, over weeks and months — not overnight.
Does When You Eat Matter?
Meal timing doesn’t change fat loss if your calories are the same. Eat at 8am or 8pm — your body cares about the total balance. Timing matters more for energy, performance, and recovery than the number on the scales.
The Takeaways
- Expect fluctuations. They’re normal.
- Track weekly averages, not single weigh-ins.
- Don’t let a Monday weigh-in after a weekend of fun ruin your week.
- Focus on your habits: eating well, training, sleeping, and not the daily number.
Final Thought
Remember that scales are just one tool. Some days they lie, some days they flatter you. Like many things in life, what matters is the long-term direction, not the short-term noise.
So, if you come back from a holiday (or even just a busy weekend) a couple of kilos heavier, then it’s not time to panic. The chances are it’s water, glycogen, and a few extra memories. And those, unlike the weight, are worth keeping.
