Nutrition with PCOS/PMOS

1.1. Overview

To understand what effect a reduction in carbohydrate intake might have on PCOS or where the idea for this more restrictive diet comes from, it is first important to gain a better understanding of the condition. This understanding begins with the name itself. In May 2026 various professional bodies agreed to rename PCOS as PMOS. Whilst the name ‘polycystic ovary syndrome’ previously focused on the polycystic ovaries - or typical changes in the ovaries – and the associated symptoms, a name change to polyendocrine metabolic ovary syndrome (PMOS) is intended to shift the focus to the entire body and metabolism. The renaming is intended to further emphasise the focus on the whole body [1,2].

The syndrome is therefore significantly more diverse than previously thought. So what difference does this new knowledge make? This shift in focus is intended to ensure that the condition is diagnosed more frequently, more quickly and treated more comprehensively [2].

To make the transition to the new name as easy as possible, both names are used as synonyms in this text.

1.2. What noticeable symptoms actually suggest the presence of PMOS?

PMOS can manifest in a wide variety of ways. Whilst some symptoms are very specific and typical of the condition, others are very non-specific and difficult to attribute to it. Typically, menstruation is irregular or may even cease altogether. In addition, above-average hair growth following a male pattern – known as hirsutism – may occur. Similarly, darker patches of skin (acanthosis nigricans) may form on the neck or under the arms. Weight may also be slightly increased and significantly more difficult to control. At the same time, a frequent urge to urinate, increased thirst, constant tiredness and a lack of energy may be signs of accompanying insulin resistance. Other associated symptoms may include sleep problems, depression, anxiety or headaches [4].

The symptoms can vary greatly in terms of their presentation and severity, which means they are not always easy to recognise [4].

1.3. Diagnosis

The diagnostic criteria for PCOS or PMOS are very clearly defined. At least two of the following three criteria (known as the Rotterdam criteria) must be met in order to make the diagnosis. For the sake of clarity, simpler terms have been used here rather than technical terminology [3].

• Clinically and/or biochemically elevated levels of male sex hormones

• Menstrual cycle disorders, often characterised by delayed or absent ovulation due to prolonged menstrual cycles of over 35 days

• An increased number of small follicles in the ovaries and/or high levels of anti-Müllerian hormone (AMH), whilst relevant differential diagnoses have been ruled out [3]

Whilst a name change has therefore been proposed, the diagnostic criteria remain the same. It is important to note, however, that the diagnosis does not automatically determine the treatment. This is determined by further metabolic changes and the symptoms. Other possible causes of hormonal imbalance should always be investigated to avoid a misdiagnosis [3].

Diagnoses should be made by suitably qualified specialist doctors.

1.4. Complications/Comorbidities

PMOS can give rise to a wide range of complications. This is because the hormonal changes can affect many parts of the body. The most common complications arise from hormonal imbalance. Elevated levels of male sex hormones (known as androgens) can lead to both a male-pattern hair distribution and increased hair loss. On the other hand, menstrual cycle disorders may occur, often involving delayed or absent ovulation. At the same time, the lining of the womb is under constant oestrogenic influence without balancing progesterone and may therefore thicken, which can lead to more severe cramps and heavier bleeding when menstruation begins. If menstruation is absent for a prolonged period, the endometrium continues to be stimulated by oestrogen without this effect being counterbalanced by progesterone. This further increases the risk of endometrial cancer [4].

More severe pain may also potentially occur for other reasons, such as increased inflammatory responses and an increased number of follicles in the ovaries [4].

Furthermore, elevated testosterone levels, insulin resistance or existing overweight can lead to sleep problems accompanied by night-time cravings and sleep apnoea. This should be investigated and treated if necessary. Symptoms such as fatigue, daytime sleepiness, snoring or a lack of motivation may be further consequences [3,4]. Various psychological symptoms, such as depression, eating disorders or anxiety disorders, may also occur and should be properly assessed and treated [3].

1.5. Metabolic Complications

As the name "polyendocrine metabolic ovarian syndrome (PMOS)" implies, it affects not only the sex hormones and the ovaries, but also the metabolism. PMOS significantly increases the risk of metabolic disorders. PMOS is a risk factor both for metabolic syndrome – a combination of abdominal obesity, elevated fasting blood glucose or insulin resistance, hypercholesterolaemia, hypertension and other factors – and for what is known as MASLD (metabolic-associated steatohepatitis). It is therefore important that appropriate investigations are carried out and any necessary treatments are administered. In particular, managing and maintaining a healthy body weight can play an important role here, as being overweight or obese can be additional risk factors for other associated conditions. At the same time, PMOS makes weight regulation more difficult, and those affected are more prone to weight gain [3,4].

One of the best-known comorbidities of PMOS is insulin resistance. Women with this condition have a five-fold increased risk of impaired glucose tolerance compared with those without the condition [3].

The difficulty, however, lies in recognising and diagnosing the condition. Whilst a test for fasting glucose and "long-term blood sugar" (HbA1c) can reveal the current blood sugar status or the blood sugar load over the past three months, these values alone do not indicate potential insulin resistance. For example, the HOMA-IR can be calculated from fasting glucose and fasting insulin levels. This is a parameter that is currently very frequently used as an indicator of existing insulin resistance.

Another alternative for measuring the body’s response to sugar is the oral glucose tolerance test (OGTT). This test assesses the body’s response to the intake of glucose (a simple sugar). It is normally used as a diagnostic tool to identify prediabetes or type 2 diabetes mellitus. However, it can also be supplemented by a parallel measurement of insulin levels. This makes it possible to determine whether increased insulin secretion is required to process the sugar in the blood. If this is the case, it may also indicate reduced insulin sensitivity. If blood glucose rises to ≥200 mg/dl after 2 hours, this is a clear diagnostic criterion for diabetes mellitus [5]. However, the diagnosis should be confirmed by a second measurement unless elevated fasting blood glucose levels have already been recorded on several occasions.

Whilst established diabetes mellitus can present with clear symptoms, insulin resistance often goes undetected. Signs of insulin resistance may include darker patches of skin under the armpits or on the back of the neck (acanthosis nigricans). Fatigue, listlessness or food cravings are more non-specific symptoms [4].

1.6. The impact of insulin resistance on PCOS/PMOS:

Whilst insulin resistance was regarded merely as a secondary symptom not so long ago, it is now believed to be a key component of PMOS and may even be a driver of hormonal imbalance [4]. Although the link between reduced insulin sensitivity in cells (insulin resistance) and elevated levels of male sex hormones has not yet been fully understood, there are some promising findings. The same applies to the cause of insulin resistance. On the one hand, it can be exacerbated by increased body weight; on the other hand, women of normal or low body weight are equally affected [4]. However, the influence of insulin resistance on PMOS and its symptoms is becoming increasingly clear and should not be overlooked. Some publications even refer to this relationship as a vicious circle [6,7].

In healthy people with no problems relating to carbohydrate metabolism, insulin levels remain moderate; when carbohydrates are consumed, these levels rise sufficiently to enable glucose (simple sugar) to be taken up from the blood into the body’s cells. However, in the case of insulin resistance, the effect of insulin on the cells is reduced and glucose cannot be removed from the blood. To compensate, even more insulin is produced in order to keep blood glucose levels stable nonetheless [8]. As a result, insulin levels are already elevated on an empty stomach, and rise even further after a meal containing carbohydrates [5,8].

According to current knowledge, the insulin resistance and the resulting elevated insulin levels present in many women with PMOS, have adverse effects in various ways. On the one hand, insulin can directly stimulate increased androgen production in the ovaries, thereby raising the concentration of these sex hormones (including testosterone). At the same time, high insulin levels inhibit the production of sex hormone-binding globulin (SHBG) in the liver. One of SHBG’s functions is to bind testosterone, thereby reducing its biologically active concentration in the blood. If less SHBG is produced, the proportion of free androgens (including testosterone) rises further, which can further exacerbate typical PMOS symptoms [7].

The treatment of PCOS addresses several issues simultaneously. On the one hand, the aim is to correct the hormonal imbalance in order to reduce the risk of complications such as thickening of the lining of the womb (caused by excessive oestrogen without balancing progesterone), diabetes, heart attacks or strokes (caused, amongst other things, by metabolic risk factors such as insulin resistance, lipid metabolism disorders and high blood pressure). At the same time, the focus is also on alleviating existing symptoms to improve quality of life and to treat any infertility that may be present [3,4].

Hormonal imbalance is often treated with medication and monitored by a doctor. However, lifestyle also plays a very important role in the management of PCOS/PMOS. Nutritional therapy is a key component of conservative management [3,4].

1.7. Nutrition with PCOS or PMOS

Dietary therapy forms a very important part of the treatment of PMOS. However, the recommendations depend heavily on the diagnosis and symptoms [4]. In cases of overweight or obesity, for example, moderate calorie restriction and the associated weight loss are recommended. This is achieved by adjusting diet and physical activity in everyday life [3]. In the long term, the aim should be to achieve a normal weight in order to counteract rising androgen production. However, in such cases, even a 5 percent reduction in weight has been shown to improve menstrual irregularities and reproductive function [3,4].

Whilst insulin resistance may be exacerbated by being overweight or obese, it can also occur in women of normal weight or who are underweight. In such cases, calorie restriction is generally not effective. For those of normal weight, the main focus should be on following the recommendations for a generally healthy diet, a Mediterranean diet or a vegetarian diet. A general reduction in carbohydrate intake has not shown any significant benefit in the majority of studies conducted to date. The macronutrient distribution (carbohydrates, fats, protein) also plays only a minor role in treatment [3].

The key principle of nutritional therapy with PCOS is the quality of nutrients. Whilst a high intake of simple or refined sugars can lead to sharp fluctuations in blood sugar and insulin levels, large amounts of dietary fibre tend to help stabilise these levels [3]. Fibre is found in fruit, vegetables, pulses and wholegrain products. It causes blood sugar levels to rise much more slowly, meaning less insulin is required at any one time. This can help to improve insulin resistance. It is also advisable to ensure an adequate intake of unsaturated fatty acids from nuts or high-quality vegetable oils, and to prioritise high-quality protein sources such as plant-based foods, fish, (low-fat) dairy products and lean, preferably unprocessed meat [3]

1.8. Conclusion

In summary, there is no convincing evidence that extreme or highly restrictive diets offer any long-term benefits. They often merely lead to severe restrictions in food choice and increased everyday stress, and offer no long-term benefits. A calorie-controlled, balanced diet rich in fibre, unsaturated fatty acids and high-quality protein sources offers the greatest benefits for those with insulin resistance. The diet for PCOS with insulin resistance therefore does not differ significantly from the general dietary recommendations of the DGE for healthy people or those with type 2 diabetes [3].

The key to successful dietary management remains its feasibility. It is therefore essential to tailor it to individual needs.

1.9. References

[1]	Teede H, Khomami M, Morman R et al., Polyendocrine metabolic ovarian syndrome, the new name for polycystic ovary syndrome: a multistep global consensus process, The Lancet, 2026; 407, 2329-2339
[2]	Mirjam Martin, PMOS statt PCOS: Polyzystisches Ovarsyndrom bekommt neuen Namen, Deutsches Ärzteblatt, 12.05.2026
[3]	Deutsche Gesellschaft für Endokrinologie e.V. et. al, S2k-Leitlinie Diagnostik und Therapie des polyzystischen Ovarialsyndroms (PCOS), AWMF online, 13.08.2024
[4]	JoAnn V. Pinkerton, Oluwatosin Goje, Polyzystisches Ovarialsyndrom (PCOS), MSD Manuals Ausgabe für medizinische Fachkreise, August 2025
[5]	IMD Berlin, Polyzystisches Ovar-Syndrom, 2026 Website: https://www.imd-berlin.de/fachinformationen/diagnostikinformationen/300-399/363-polyzystisches-ovar-syndrom-pcos
[6]	Deutsche Gesellschaft für Endokrinologie, Polyzystisches Ovarsyndrom (PCOS) geht oft mit Typ 2 Diabetes einher, 2021, Pressemitteilung: https://www.endokrinologie.net/pressemitteilung/pcos-typ-2-diabetes.php
[7]	Xin Zeng, Yuan-jie Zie, Ya-ting Liu, Shuang-lian Long, Zhong-cheng Mo, Polycystic Ovarian Syndrome: Correlation Between Hyperandrogenism, Insulin Resistance and Obesity, 2019, Clinica Chimica Acta, Volume 502
[8]	Cleveland Clinic, Insulin Resistance, 2024, Website: https://my.clevelandclinic.org/health/diseases/22206-insulin-resistance