How much weight can you lose in a month? A realistic pace

September 23, 2026approx. 17 minutesby mybody®x Editorial & Expert Team

In this article

How much weight can you lose in a month according to the guideline?

Approx. 2 kg in four weeks, extrapolating the guideline’s weekly figure. This is a calculation, not a prediction for you.

The figure comes from the S3 Guideline on Obesity, published in 2024 by the German Obesity Society (DAG); S3 is the highest development level for a guideline. A guideline is a medical recommendation that a professional association derives from the available studies and the consensus of its experts. The recommendation on the energy deficit is one such expert consensus, approved by 94 percent of those involved.

It assumes an energy deficit, meaning fewer calories each day than the body uses. This energy is measured in kilocalories (kcal), the unit used for the energy content of food and drink. In the words of the guideline: “An energy deficit of approx. 500 to 600 kcal/day is usually targeted. This can be expected to result in weight loss of approx. 0.5 kg per week over a period of no more than three months.” The guideline also explicitly allows for an individually determined deficit. For guidance on estimating your own needs, see the article Calories per day for weight loss: how to estimate your needs.

Extrapolating the weekly figure gives about 1.5 kg in three weeks and about 2 kg in four weeks. The calculation is sound as long as you keep its limit in mind: the guideline gives the weekly figure only for the first three months. After that, weight loss slows, and according to the guideline, it does so rapidly.

Four figures from the S3 Guideline on Obesity

Source: German Obesity Society (DAG), S3 Guideline on Obesity, recommendations 5.3 and 5.11, 2024

The third figure in the strip is the most revealing. After twelve months, the guideline expects 5 to 6 kg, regardless of which diet someone follows. So the weekly figure cannot be extrapolated over a year.

Weight loss per week and month: Which figure applies when?

For the first three months, the weekly figure is about 0.5 kg. For the period up to one year, the guideline specifies targets in percentages and an expected annual figure.

The first week goes well, and the scales show a clear drop. In the second week, little changes; in the third, a bit more. If you then compare your progress with a figure from an app or magazine, you may feel confused because the numbers contradict each other. They contradict each other because they refer to different periods.

The overview therefore separates two types of figures. One is stated verbatim in the guideline. The other is a calculation based on the weekly figure and applies only as long as the weekly figure itself does, that is, for no more than three months. If you have a specific goal in mind, such as losing five kilos by a certain date, you can find a suitable timeline in the article Losing 5 kilos: a realistic timeline.

Read the table from top to bottom like a curve. At the top are short periods with a fixed weekly figure; at the bottom, the long stretch for which the guideline thinks in percentages.

Weight loss by period

What weight-loss goal does the guideline give instead of a monthly figure?

At least 5 percent of initial body weight for a BMI of 25 to 34.9, and at least 10 percent for a BMI of 35 or higher, in each case over six to twelve months (DAG, 2024).

This target is more sustainable than any monthly figure because it is not measured in weeks, but in relation to where you start. The guideline sets not a range, but two thresholds, depending on how high the BMI is at the outset. Both are formulated as minimum values, not upper limits.

The background text explains why the S3 guideline (DAG, 2024) sets its sights on 5 percent: According to DAG 2024, weight loss of approximately 5 percent already leads to a significant, statistically proven improvement in cardiometabolic risk factors. These are risk factors for cardiovascular health and metabolism. This explains why the guideline sets a relatively modest target and still considers it important.

How achievable are these goals? The guideline contains a sentence that carries more weight than any weekly figure.

In medicine, conservative means treatment without surgery. The sentence contains two messages. The goals can be achieved without intervention. Conversely, even in supervised programs, some people do not reach the goal. Not reaching the goal within six to twelve months does not make you an exception.

Why is the first month of weight loss misleading?

Because some of the initial weight loss is water. Glycogen, the storage form of carbohydrates, is stored with three to four parts water (Kreitzman and colleagues, 1992).

You can think of glycogen as a stockroom where each box of carbohydrates is stored on a shelf packed with three to four boxes of water, including in the liver and muscles. Whatever the stockroom supplies comes with its packaging. Kreitzman and colleagues describe in the American Journal of Clinical Nutrition how this water-laden glycogen causes weight to fluctuate during a diet. Their article’s title already refers to the “illusions of easy weight loss.”

There is no reliable way to quantify how many kilos of water this amounts to. The study observed 11 people over 4 days on a very low-calorie diet and gives no figure in kilograms. But it also describes the reverse: an exaggerated regain when carbohydrate stores are replenished. So a jump on the scale after days of eating lots of carbohydrates does not necessarily mean new fat.

The first few weeks are therefore a poor measure of the overall trajectory. The article losing weight quickly in one week explores why a few fast weeks say little about fat loss. An overview of the four phases:

The four phases

Why does the rate of weight loss slow after three months?

Because the body activates energy-saving mechanisms and loses muscle mass along with weight, and muscle uses energy at rest. That’s how the S3 Obesity Guideline describes it (DAG, 2024).

The guideline identifies two processes that happen at the same time. The body activates energy-saving mechanisms, so weight loss quickly slows down. In addition, weight loss also includes a loss of fat-free mass, meaning everything that is not fat, especially muscle tissue. This reduces resting energy expenditure, the energy the body needs without any activity.

The same pattern appears in an analysis of 80 studies published by Franz et al. in the Journal of the American Dietetic Association in 2007. In programs with reduced energy intake, sometimes supplemented with medication, weight loss plateaued at around six months, meaning the weight stopped declining. In studies lasting up to 48 months, on average, none of the groups returned to their starting weight.

For the question of how weight loss changes month to month, this means that losing less in the fourth month than in the second is consistent with the pattern described in the guideline.

The role hormones and genes play in this adaptation is a separate question. This article focuses on the pace of weight loss. Why weight loss is so difficult explains the underlying mechanism. If your weight stops changing altogether after months, that’s a different issue from a slowing pace of weight loss: Weight loss plateau: how to overcome it.

Are two common claims about rapid weight loss true?

No. Some of the rapid initial loss is water, and although cutting back more leads to greater weight loss, it triggers similar adaptations in the body.

Both statements sound plausible because they reflect real experiences. The first few weeks bring quick results, and people who cut back more see a bigger drop on the scale in the short term. The sources show why neither should be treated as a rule.

Two statements checked against the source

The choice of diet also changes the pace less than its reputation might suggest. Sacks and colleagues assigned 811 adults with overweight to four calorie-reduced diets that differed significantly in how much energy came from fat and how much from carbohydrates (New England Journal of Medicine, 2009). After six months, participants in every group had lost an average of 6 kg, or 7 percent of their initial body weight.

The authors’ conclusion: Calorie-reduced diets lead to significant weight loss, regardless of which macronutrients they emphasize, meaning which of the main energy-providing components of food. Accordingly, the deficit matters more for the pace than the diet’s label.

Losing 1 kg per week: What speaks against it?

Losing 1 kg per week is twice what the guideline expects during the first three months. Greater weight loss is possible with a larger deficit, but the body adapts in a similar way (DAG, 2024).

The number is round and tangible, and it appears in search queries. It is not in the guideline. The guideline only states that a higher energy deficit can lead to greater weight loss, but that similar physiological adaptation mechanisms occur, meaning similar energy-saving responses by the body that also slow the pace with a moderate deficit.

There is also a calculation that is easy to overlook. Even if you manage to lose one kilo in a week, it says little about the following months. For the usual deficit, the guideline expects a loss of 5 to 6 kg after twelve months (DAG, 2024), regardless of which dietary therapy someone chooses. So one fast week does not mean a fast year.

This does not mean that a different pace is prohibited. The guideline explicitly recommends an individually determined deficit. If you want or need to lose weight faster, it is best to set that deficit together with your primary care practice rather than deriving it from an app calculation.

What can a DNA test do to help with weight loss, and what can’t it do?

A DNA test cannot predict weight-loss success. The S3 guideline’s target remains a sound benchmark (DAG, 2024): at least 5 percent of initial body weight for a BMI of 25 to 34.9, and at least 10 percent for a BMI of 35 or higher, in each case over six to twelve months.

A DNA test examines gene variations, small differences in genetic material that vary from person to person. It does not measure how quickly you lose weight. It also does not make a diagnosis or replace a medical examination.

A position paper by the German Nutrition Society (DGE) noted in 2022 that evidence for the effectiveness of gene-based dietary recommendations was still largely lacking (paraphrased from Holzapfel et al., 2022). We therefore see the value of a DNA test in providing structure and context, not a diagnosis. Applied to the pace of weight loss, this means that a DNA test does not change the approximately 0.5 kg per week expected by the guideline. Your genetic makeup isn’t a foregone conclusion.

Those looking for this kind of starting point for their own approach can find WeightLoss in the mybody®x range (MYBODY Lab GmbH) | SLIM DNA Test. It analyzes over 80 gene variations from a saliva sample and summarizes them in 24 analysis reports. The test interval is once in a lifetime. The SLIM does not assess individual foods.

Limitations: What doesn’t the monthly figure for weight loss tell you?

It doesn’t reveal how much of the loss is fat. And it’s no promise for any one person.

The guideline’s figures describe what to expect with a specific deficit. They don’t say what will happen to you. The scale doesn’t distinguish between water and fat, and both are involved, especially in the first month (Kreitzman and colleagues, 1992). Fat-free mass is also lost along with weight (DAG, 2024). A number on the scale is therefore a rough indicator, not a finding.

The test also has limitations. They belong here, not at the end. A DNA test is not a diagnostic tool and does not replace a medical examination. It cannot predict how much weight you will lose in a month, and genetic variants describe probabilities in population groups, not a predetermined outcome for you.

The guideline was written to support medical care, not as a self-test. If food and weight are dominating your everyday life, your doctor’s office is the first place to turn, not a chart.

How do you interpret your own rate of weight loss?

Over months, not days, and measured as a proportion of your starting weight rather than a fixed number of kilos per month.

Three weeks at around 1.5 kg and four weeks at around 2 kg are figures calculated from the guideline, not a benchmark you can fail to meet. More useful is the question the guideline itself asks: What percentage of your starting weight have you lost after six to twelve months?

A calculation example shows how modest this target is. If you start at 90 kg with a BMI between 25 and 34.9, the guideline target of 5 percent (DAG, 2024) is 4.5 kg, to be reached in six to twelve months. Spread over six months or longer, that’s a modest target.

So read your progress in phases. The first few weeks include water loss, after the third month the curve flattens, and eventually it’s about maintaining your weight. If you use the first week as your benchmark, you’re measuring yourself against the illusion that Kreitzman et al. described back in 1992.

Around 2 kg a month by calculation, and only during the first three months (DAG, 2024): This isn’t a judgment about you, but a point of reference. And the scale alone can’t give you that.

Frequently asked questions

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Sources

1. German Obesity Society (DAG) e.V.: S3 Guideline on Obesity – Prevention and Treatment, Version 5.0, AWMF 050-001 (as of 2024) – register.awmf.org
2. Kreitzman SN, Coxon AY, Szaz KF: Glycogen storage: illusions of easy weight loss, excessive weight regain, and distortions in estimates of body composition. American Journal of Clinical Nutrition (1992) – europepmc.org
3. Franz MJ et al.: Weight-loss outcomes: a systematic review and meta-analysis of weight-loss clinical trials with a minimum 1-year follow-up. Journal of the American Dietetic Association (2007) – europepmc.org
4. Sacks FM et al.: Study of 811 adults on four calorie-restricted diets, New England Journal of Medicine (2009), PMID 19246357 – europepmc.org

The rate of weight loss, energy deficit, target milestones, and the quote on achievability are based on [1]. Glycogen's water retention is based on [2], the plateau at around six months on [3], and the comparison of diet types on [4]. The DGE position follows in spirit the position paper by Holzapfel et al., Molecular Nutrition and Food Research 2022, DOI 10.1002/mnfr.202200077. Product details are based on the mybody®x product page; price checked on September 23, 2026.