How Much Weight Can You Safely Lose per Week?
Last updated: August 2026
The standard guidance is 0.5 to 1 kg (1 to 2 lb) per week - not caution for its own sake, but the rate at which the loss is mostly fat, the plan is sustainable, and the risks of rapid loss stay off the table.
Here's the arithmetic, why week one always beats it, and what going faster costs. One reframing up front: 0.5-1% of body weight per week scales better than a fixed number - what's sensible at 120 kg is aggressive at 60 kg. Your rate only ever shows in weekly averages, never single mornings.
The deficit math
A kilogram of body fat stores roughly 7,700 calories (about 3,500 per pound). Divide by seven for the daily gap each rate requires:
| Target rate | Weekly deficit | Daily deficit | Realistic for |
|---|---|---|---|
| 0.25 kg (0.5 lb) / week | ~1,900 kcal | ~275 kcal | Fine-tuning near your goal; preserving muscle |
| 0.5 kg (1 lb) / week | ~3,850 kcal | ~550 kcal | The default sensible target for most adults |
| 0.75 kg (1.5 lb) / week | ~5,750 kcal | ~825 kcal | Higher starting weights, with good adherence |
| 1 kg (2 lb) / week | ~7,700 kcal | ~1,100 kcal | The upper end of the standard guidance |
| 1.5 kg (3 lb)+ / week | ~11,500 kcal+ | ~1,650 kcal+ | Rarely achievable without medical supervision |
The bottom rows show the problem: an 1,100-calorie daily deficit is a third to a half of most people's energy needs, and a 1,650-calorie deficit exceeds what many burn in a day at all. Very rapid loss is the province of medically supervised programs.
One caveat: the rule overestimates long-run loss, because a lighter body burns less. Real results run slower than the table after month one - normal, and the mechanism behind most weight loss plateaus.
Why the first week always beats the estimate
Almost everyone loses 2-4 kg (4-8 lb) in week one, whatever the plan - and it isn't fat. Cutting calories, especially carbs, empties the glycogen tank - and each gram of glycogen takes three grams of water with it. Three consequences:
- Don't extrapolate it. 3 kg in week one doesn't mean 12 kg a month; weeks two to four reveal the true rate.
- Don't panic in week two. When loss drops to 0.6 kg, nothing broke - the water is gone.
- A 2 kg jump after a carb-heavy weekend is the same effect backwards. The tank refilled; 2 kg of fat would take roughly 15,000 extra calories.
Hence the weekly average: the water noise dwarfs the signal.
What goes wrong when you go faster
Faster isn't braver. Aggressive deficits carry documented costs:
- More muscle lost. Bigger deficits take a bigger share from lean tissue - lowering your maintenance level, the classic setup for regain.
- Gallstones. Rapid loss is a well-recognized risk factor - supervised programs monitor for it.
- Nutrient shortfalls. It gets hard to cover protein, iron, calcium and B vitamins - fatigue, hair thinning and poor recovery follow.
- Deeper adaptation. Steep deficits amplify the drop in resting expenditure and everyday movement - the stall arrives sooner.
- Hormonal disruption. Prolonged severe restriction can affect menstrual cycles and bone health.
- Adherence collapse. The most common outcome: crash diets have poor completion rates, and regained weight returns with worse body composition.
Very-low-calorie diets have a legitimate place - under medical supervision, for clinical reasons, with monitoring. That's a treatment plan agreed with a doctor, not improvised from an article.
Choosing your rate
Aim for 0.5-1% of current body weight per week, lower half as default:
| Current weight | 0.5% / week | 1% / week |
|---|---|---|
| 60 kg (132 lb) | 0.3 kg (0.7 lb) | 0.6 kg (1.3 lb) |
| 80 kg (176 lb) | 0.4 kg (0.9 lb) | 0.8 kg (1.8 lb) |
| 100 kg (220 lb) | 0.5 kg (1.1 lb) | 1.0 kg (2.2 lb) |
| 120 kg (265 lb) | 0.6 kg (1.3 lb) | 1.2 kg (2.6 lb) |
Adjustments:
- Slow down near your goal. The closer to a healthy weight, the more of the loss is muscle - the last 5 kg should be the slowest.
- Protect lean mass. Adequate protein and lifting twice a week shift the loss toward fat. If you lift, the scale understates progress - body fat percentage tells it better.
- Expect a staircase, not a slope. Two good weeks, a flat one, a small rise, a drop - judge monthly.
And plan the part everyone skips: holding a new weight is a skill, and it decides whether the rest was worth it.
Notebook, spreadsheet, or app: an honest comparison
A notebook column of weekly averages plus a calculator gives your real rate. The tedious part: rates need history - this month's average against last month's, against the 0.5-1% band, over a quarter.
Weight & BMI Feeltracker is free and does that part: charts and trend lines over any period, so "too fast?" is a glance at a slope; goal tracking that turns a distant target into a visible rate; weight, BMI and body fat together, since rate and quality of loss are different questions; reminders, widgets, photos and Apple Health sync; export to PDF, XLSX, CSV or JSON; iCloud sync with no account or email; and AI insights in the free tier.
Either way: pick a rate you could still run in six months, and measure it in weeks, not days.
Frequently asked questions
How much weight can you lose in a week safely?
The standard guidance is 0.5 to 1 kg (1 to 2 lb) per week, or 0.5-1% of current body weight per week, which stays sensible at both 60 kg and 120 kg. Larger starting weights can sit at the higher end; the closer you are to your goal, the slower it should be.
Is losing 2 kg a week too fast?
For most people, yes - roughly double the upper end of the guidance, typically with a larger share of muscle lost and higher risks including gallstones and nutrient shortfalls. Loss at that pace belongs in a medically supervised program, not a self-directed plan.
Why did I lose 3 kg in my first week?
Glycogen and the water stored with it, plus less food in transit and lower sodium. It's real weight but it isn't fat, and it doesn't repeat - your true rate shows up in weeks two to four. See why your weight fluctuates daily.
How big a calorie deficit do I need?
Roughly 550 calories a day for 0.5 kg (1 lb) per week, about 1,100 for 1 kg (2 lb), based on around 7,700 calories per kilogram of fat. The estimate overshoots over time, because a lighter body burns less - expect slower loss from the same deficit after the first month.
Why did my weight loss slow down after a month?
Your maintenance level fell with your weight, so the deficit you set is now smaller - and everyday movement tends to drop unconsciously in a deficit. Both are normal and fixable: work through how to break a weight loss plateau.
