Posted on June 24, 2025 by Kate Halsall
Step on the scales in the morning, and you’re up a kilo. Step on again after a workout, and you’re down the same amount. Sound familiar?
For many clients (and let’s be honest, for many PTs too), the scale can feel like a rollercoaster — sometimes helpful, sometimes confusing, and sometimes emotionally draining.
Today, I weighed myself before a run and then again after. I was one kilo lighter post-run. But I also knew this morning’s weight was higher than usual — I’d eaten later than normal the night before and had something salty. So… what was real?
The answer? All of it. And none of it.
Let’s break it down.
1. Weight Fluctuates. A Lot.
It’s completely normal for your body weight to fluctuate by 1–2kg daily (sometimes more), and it’s rarely fat gain or loss.
Your weight is influenced by:
- Hydration levels
- Glycogen stores
- Food volume still in your gut
- Salt intake
- Hormones
- Sleep quality
- Stress and cortisol
- When you last went to the toilet
So that “extra kilo” in the morning? It could be water retention from salty food. That quick loss post-run? It’s sweat, not fat burning.
2. The Scale Is a Tool — Not a Truth-Teller
Scales measure weight, not fat. That’s an important distinction.
- If you strength train and build muscle, the number might go up — even as your shape changes.
- If you’re dehydrated, it might go down — but that doesn’t mean you’ve lost fat.
- You could weigh the same for weeks, but drop inches and fit your clothes differently.
What matters most: trends over time, not individual data points.
3. So… How Often Should You Weigh Yourself?
That depends on your mindset, goals, and relationship with the scale.
Here’s what we see with clients:
| Weigh-in Habit | Benefits | Drawbacks |
|---|---|---|
| Daily | Good for data tracking if you’re emotionally detached | Can lead to obsession or discouragement if you don’t understand fluctuations |
| Weekly | Balances trend-watching with less emotional stress | Still influenced by daily variables |
| Occasionally | Great if you track other progress markers too (measurements, strength, how clothes fit) | Less data, harder to spot trends |
| Not at all | Best for some clients focused on mindset, performance, or behaviour change | Can feel disconnected from a goal like fat loss |
There’s no “right” answer — just the one that supports your mental health, motivation, and goals.
4. What You Can Do Instead
If the scale stresses you out, consider tracking progress in other ways:
- Strength and fitness levels
- How your clothes feel
- Before/after photos
- Energy, mood, and sleep
- Body measurements
- How consistent you’ve been with habits
Remember: weight loss and fat loss are not the same — and neither are health and a number on a scale.
Final Thoughts
Whether you weigh yourself every day or not at all, just know this: your worth, progress, and health cannot be measured by a single number.
Use the scale as just one piece of the puzzle — not the whole picture.
If you ever feel unsure about what the numbers mean (or whether you should even be using them), chat with your Personal Trainer. There are plenty of ways to track progress — and the best method is the one that works for you, not against you.