Weight Fluctuation: What To Do
The day-to-day movement on the scale that has nothing to do with body fat.
Last revised
Misreading normal fluctuation as failure is one of the commonest reasons people abandon plans that were working.
Key takeaways
- Normal daily fluctuation: 1-2kg
- Calorie surplus to store 1kg of fat: roughly 7,000 calories
- Most useful single change: Read the weekly average, never a single morning.
- Commonest mistake: Changing your plan on the strength of one reading.
- See a doctor if any of the signs under "When to get help" below apply to you.
Do
- Read the weekly average, never a single morning
- Weigh under identical conditions each time
- Track your waist as well as your weight
- Expect a rise after a high-carbohydrate or high-salt day
Do not
- Changing your plan on the strength of one reading
- Reading a fast first week as fat loss; much of it is water
- Weighing daily if it makes you anxious
The figures behind the list
Each item above follows from these, published in the guidance named at the foot of the page.
| Measure | Figure |
|---|---|
| Normal daily fluctuation | 1-2kg |
| Calorie surplus to store 1kg of fat | roughly 7,000 calories |
| Water bound per gram of glycogen | about 3g |
| Minimum data before judging a trend | 3-4 weeks |
| Useful companion measure | waist circumference |
Where to go next
- The Weight Fluctuation Checklist: What to Do and What to Skip
- Myths About Weight Fluctuation, Checked Against the Guidance
- Weight Fluctuation — the reference entry
- The Evidence on Weight Maintenance, Without the Hype
- Energy Balance: What the Evidence Actually Says
When to get help
See a GP for unexplained weight loss you did not intend, or rapid weight gain over days with leg swelling or breathlessness, which can indicate heart or kidney problems. If weighing has become compulsive, speak to your GP; the Beat helpline is 0808 801 0677.
Where this comes from
- NHS — Start the NHS weight loss plan
- British Dietetic Association — weight management
How this page was put together
Every figure, recommendation and warning above is taken from the guidance named in Where this comes from. Nothing on this page is inferred, summarised or generalised beyond what those bodies publish: where they give a number, it is their number, and where they are silent, so are we. Pages are rebuilt whenever the underlying record changes. Sign-off by a named clinician, where it has happened, is shown at the top of the page along with the date.
Medical disclaimer
This article is general information, not medical advice. It cannot account for your own history, medication or circumstances. Always speak to a GP, pharmacist or another qualified health professional before making changes that affect your treatment, and never delay seeking medical advice because of something you have read here. In an emergency, call 999.