Setting a target weight implicitly sets a rate as well. Twelve kilos in three months is a very different proposition from twelve kilos in a year, and usually only one of the two can be sustained without side effects.
The rule of thumb: 0.5 to 1 percent per week
In sports nutrition, a weekly loss of 0.5 to 1 percent of body weight is the common recommendation. The advantage of stating it relatively is that it scales automatically. One kilo per week is moderate at 110 kg and aggressive at 60 kg.
| Starting weight | 0.5 % per week | 1 % per week |
|---|---|---|
| 60 kg | 0.30 kg | 0.60 kg |
| 80 kg | 0.40 kg | 0.80 kg |
| 100 kg | 0.50 kg | 1.00 kg |
| 120 kg | 0.60 kg | 1.20 kg |
The upper end suits the beginning and people with plenty of reserve. The closer you get to your target weight, the further you should move towards the lower end, because otherwise the share of muscle mass in the loss increases.
Roughly converted, half a kilo of fat per week corresponds to a daily deficit of around 500 kilocalories. That calculation is an approximation, not a law of nature: energy expenditure falls as weight falls, and the body adapts over weeks.
Why faster is rarely better
Muscle loss. With very large deficits, a growing share of the loss comes from fat free mass. Less muscle means a lower basal metabolic rate, so a smaller deficit at the same calorie intake. The fast route makes the rest of the route harder.
Sustainability. A deficit that produces hunger, poor concentration and irritability is rarely maintained for more than a few weeks. The average rate over twelve weeks is the number that counts, not the rate of the first ten days.
The initial drop is deceptive. In the first week many people lose two to three kilos. Most of that is glycogen and the water bound to it, not fat. Taking that first week as the benchmark makes every following week look like a setback.
How to measure your actual rate
Do not take the difference between two daily values. Take the 7-day change of your trend weight, that is today's smoothed value against the one from a week ago. Why that is the only usable approach is explained in Trend weight instead of the daily value.
It becomes even more stable when you average over a longer period: the change of the trend over 30 days, divided by 4.3, gives a weekly rate that barely depends on individual weeks any more. Trendcurve shows these numbers as the balance over 7, 30 and 90 days.
The target date comes from the same rate: if you have 6 kg to go and your rate is 0.45 kg per week, that is roughly 13 weeks. If the rate slows down the date moves, and that is exactly as it should be.
Plateau or just water?
A trend running sideways for two weeks feels like a plateau. Most of the time it is not one.
Suspect water retention when:
- the trend suddenly flattens after a phase of clear loss,
- you trained hard, slept badly or ate a lot of salt shortly before,
- the cycle is in its second half,
- daily values still scatter widely without drifting upwards.
Such phases often resolve themselves within a few days, sometimes with a sudden drop of a kilo on a single morning. Fat loss was continuing the whole time, it was just hidden by water.
Suspect a real plateau when:
- the trend is flat or slightly rising over three to four weeks,
- the spread of the daily values is normal,
- something has changed in daily life: more snacks, larger portions, less movement, more restaurant meals.
The most common cause of a real plateau is not the famous "starvation metabolism" but the gradual creep of portion sizes combined with a lower expenditure. Ten kilos less body weight means, depending on height and activity, roughly 150 to 250 kilocalories less daily expenditure. The deficit from back then is no longer a deficit today.
What to do about a real plateau
- Wait two weeks and keep measuring. Without a clean basis in data, any change is guesswork.
- Track instead of estimating. A week of honest logging usually reveals the gap between the perceived and the actual amount.
- Increase activity before cutting calories. Everyday movement is the item that quietly declines the most during a diet.
- Take a diet break. Two weeks at maintenance are not a setback. In Trendcurve you record this as a trend marker so you know later why the curve is flat there.
- Reassess the goal. Sometimes it is not the rate that is wrong but the goal. Switching to "maintain" is a legitimate decision, not a capitulation.
The right expectation
What is realistic is a trajectory that points downwards on average over months and contains several flat weeks along the way. Holding 0.4 kg per week over half a year makes you ten kilos lighter. Aiming at two kilos a week leaves you exhausted after six weeks and usually back where you started.
The trend is not only a measuring tool but also a patience tool: it shows progress on days when the scale claims the opposite. Why it does that is explained in Why your weight fluctuates every day.