Polycystic ovary syndrome (PCOS) affects millions of women across the world, but there’s a significant underestimate of the number of women who fall under the lean PCOS category, where women with a normal or low BMI are diagnosed with PCOS. It is essential that we understand the unique symptoms and treatment options for those women with lean PCOS.
In this blog post, we aim to help our readers by providing information about what lean PCOS is and the different nutrition and lifestyle treatment options available.
Table of contents
- Lean PCOS vs PCOS: What Is Lean PCOS?
- What Are The Lean PCOS Symptoms?
- What Are The Four Types of PCOS?
- PCOS With Regular Periods: Is It Possible?
- Is Lean PCOS Diagnosis Different?
- How Does PCOS Differ In Larger or Smaller Bodies?
- Can Lean PCOS C ause Diabetes or Insulin Resistance ?
- Lean PCOS Belly: Visceral or Organ Fat Storage
- Is Lean PCOS Worse?
- Considerations for Women in Larger Bodies with PCOS
- Lean PCOS Treatment Options
Lean PCOS vs PCOS: What Is Lean PCOS?
Most women with polycystic ovary syndrome (PCOS) will have a larger body and may struggle with weight loss, but there is a subset of women with lean bodies with PCOS.
Only about 20% of women with PCOS will have a normal or low body mass index (BMI) and may lack usual symptoms like irregular menstrual cycle or acne (1). For these reasons, it’s easy for these patients to be overlooked or undiagnosed.
What Are The Lean PCOS Symptoms?
One of the complicated things about PCOS is that there are differences in the phenotypes (the symptoms that a woman may show and how severe those symptoms are) regardless of their weight or body composition.
To make matters even more complicated, women from different ethnic backgrounds may also show differences in their symptoms or phenotypes. For example, women of East Asian descent who have PCOS and high levels of testosterone in their blood are less likely to show physical signs of high testosterone (hair loss, acne, or facial hair).
Women who have PCOS without weight gain may also have differences in how they show symptoms as well! However, regardless of BMI women with PCOS are more likely to have higher insulin levels, insulin resistance, disrupted hormonal levels such as testosterone, thickening of the uterus lining, and physical symptoms such as irregular periods, acanthosis nigricans (darkening of skin creases) and facial hair growth (1).
What Are The Four Types of PCOS?
To learn more about the four types of PCOS, check out our other blog post. Based on the available research, it seems that women with normal weight and PCOS seem to have less severe symptoms of PCOS which would point to Type C or Type D PCOS.
PCOS With Regular Periods: Is It Possible?
Yes! You can have PCOS with regular periods! An irregular or absent period is only 2 out of the 3 diagnosis criteria for PCOS. If you have PCOS with regular periods, you may have Type C PCOS!
You can have Type C PCOS whether you are in a smaller or larger body so regular periods may be a part of lean PCOS as well!
Is Lean PCOS Diagnosis Different?
No, the diagnosis of lean PCOS is not different from PCOS. However, there are several conditions that can imitate lean PCOS, and it’s crucial that your Doctor can rule them out through proper blood work before considering lean PCOS management options.
Such conditions include congenital adrenal hyperplasia (CAH), androgen-secreting adrenal or ovarian tumors, Cushing’s syndrome, acromegaly, hyperprolactinemia, thyroid disorders, and certain medications that can cause hirsutism.
Another condition that may mimic lean PCOS is hypothalamic amenorrhea which can result from undereating and/or overexercising. A Doctor and Dietitian would be able to help you restore your period if this was the cause of your symptoms that resemble PCOS.
By being aware of and carefully investigating these conditions, healthcare professionals can accurately diagnose and differentiate lean PCOS from its look-alike conditions, paving the way for appropriate management strategies.
By understanding the intricacies and nuances of each condition, healthcare professionals can ensure optimal care for individuals with PCOS.
How Does PCOS Differ In Larger or Smaller Bodies?
Women with larger bodies tend to experience more metabolic issues. Compared to women with lean PCOS, women with PCOS in larger bodies are more likely to have high testosterone, irregular or missed periods, type 2 diabetes, high blood sugar, or thickening of the uterus (1). Check out our other blog on conditions linked to PCOS.
Women in larger bodies may experience the thickening of the uterine lining more often than women in smaller bodies. In women without PCOS, the uterine lining thickens to prepare for pregnancy. When pregnancy doesn’t occur, the uterus sheds the thickened lining, thus causing menstruation.
In PCOS, menstruation can be irregular, causing the uterine lining to remain thick. Heavy bleeding or short cycles accompany this condition. This is troublesome because, without regular shedding of the uterine lining, cells remain congregated and could eventually lead to cancer.
Studies have reported that women with PCOS have a 3.7-17 times increased risk of developing endometrial cancer than women without PCOS. (2, 3) Of interest, diabetes, and high BMI are also risk factors for endometrial cancer, which tend to go along with PCOS.
Can Lean PCOS Cause Diabetes or Insulin Resistance?
Still, women with lean PCOS face metabolic challenges. Compared to women without PCOS, women with lean PCOS have higher bad (LDL) cholesterol, insulin levels, and the liver enzyme gamma-glutamyl transferase (GGT).
Both high levels of LDL cholesterol and GGT increase the risk of cardiovascular disease, while high levels of insulin increase the risk of developing diabetes (1).
A study of 450 South Asian women compared overweight and obese (BMI ≤23) women with PCOS to lean (BMI <23) women with PCOS. While irregular periods and high testosterone were found mostly in the overweight/obese group, clinical and health indicators weren’t uncommon in lean women with PCOS.
Rates of abdominal obesity and high blood pressure were similar in both groups (regardless of BMI).
Although more women with larger bodies had high blood sugar and diabetes, lean women still experienced these issues at an increased rate compared to other healthy, young women. (4)
Another very small study of 26 women compared healthy lean women to women with PCOS in smaller bodies. The PCOS group was found to have more viscous (thicker) blood, which can lead to various cardiovascular problems.
This could result in the hardening of the arteries, narrowing blood vessels, lack of blood flow to tissues or organs, or forming blood clots in the veins – all serious and potentially fatal conditions (5).
Furthermore, the antioxidant defense system was found to be compromised in lean women with PCOS (1).
Antioxidants are important to neutralize harmful (oxidated) molecules in the body. Without antioxidants, our cells are at risk of oxidative stress, which can lead to several other health conditions like heart disease or cancer.
It is clear – outer appearance doesn’t determine your health.
And having a larger body does not mean that you “caused” your PCOS and losing weight will not “cure” your PCOS either!
Lean PCOS Belly: Visceral or Organ Fat Storage
While there’s the assumption that a larger body has more health risks, that may not be true for women with PCOS. That’s because their levels of visceral obesity – the fat around organs – are similar in lean and obese women with PCOS.
The study was on the smaller side with only 167 women (81 women with PCOS and 86 controls without PCOS), but it did have some interesting findings.
The PCOS group and healthy control group both had about half of the participants considered normal weight (BMI <25) or obese (BMI ≥25). To be clear, obesity technically starts at a BMI >30, so this study grouped overweight and obese women into one category.
Besides that, they found that regardless of BMI, visceral fat tissue (the fat around organs) is similar for women in smaller and larger bodies with PCOS. The women with PCOS in the study had phenotype D (nonhyperandrogenic PCOS) or phenotype A (classic PCOS).
As expected, type A was seen mostly in women with larger bodies and less frequently in women with smaller bodies. Women in the obese category were also more likely to have metabolic syndrome, diabetes, or insulin resistance, but body size didn’t appear to matter much for high blood sugar.
In comparing the healthy controls to the women with PCOS, women with PCOS tended to have more total body fat, abdominal fat, and visceral fat, regardless of BMI (6). Check out our other blog on the PCOS belly for more information.
Is Lean PCOS Worse?
Lean PCOS is not worse than PCOS with weight gain or obesity but it does bring its own challenges. What can be more difficult with lean PCOS is getting a diagnosis before you have fertility issues or you develop a chronic disease.
For example, if you have a regular cycle, polycystic ovaries, and high levels of testosterone in your blood but you do not show physical signs of high testosterone, you may not get a diagnosis as quickly as someone who is in a larger body or has an irregular cycle or who has physical signs of high testosterone.
To make matters more complicated, you may not realize your cycle is irregular until you get off of birth control if you have been on birth control since you were a teenager!
Now at Edge Nutrition, we are not anti-birth control as it is a useful treatment for many women with PCOS. Since many women have this question, we wrote another blog post on treating PCOS without weight loss or the pill, you can check it out for more tips.
Considerations for Women in Larger Bodies with PCOS
One of the goals for women with PCOS in larger bodies is weight loss. A loss of just 5-10% is sufficient to improve insulin, testosterone, and menstrual hormones (7). Some studies have seen successful weight loss when also using inositol in combination with weight loss strategies.
If pregnancy is a goal, it should be noted that lean women with PCOS have a higher success rate of in-vitro fertilization (IVF) compared to overweight women with PCOS (BMI >25). Adding physical activity can further improve infertility.
Lean PCOS Treatment Options
The goal for women with PCOS in smaller bodies is to maintain weight by consuming a nutrient-dense diet and being physically active.
While women with lean PCOS don’t need to alter their caloric intake, they could benefit from a more balanced macronutrient distribution. Women should include lean proteins, low glycemic index carbohydrates, and healthy unsaturated fats in their diets to help reduce inflammation. (1, 7)
How To Treat Lean PCOS: Is There A Lean PCOS Diet?
While no one diet has been proven to be superior for women with PCOS, the Mediterranean diet may be a suitable option due to its antioxidant properties.
As mentioned above, women with lean PCOS have been found to have a reduced antioxidant defense system, so fueling the body with lots of antioxidants is vital to preventing the accumulation of harmful molecules in the body.
The Mediterranean diet also helps to reduce the intake of pro-inflammatory saturated fats. Further, whole grains and starchy vegetables constitute low glycemic index carbohydrates, which are beneficial for improving insulin resistance and regulating blood sugars (7).
While the Mediterranean diet provides ample nutrients, some nutrients aren’t as easily attained through just diet.
Besides that, women with PCOS and women with larger bodies can have higher nutrient demands. Check out our other blog on how to find a PCOS meal plan that is a good fit for you!
Lean PCOS Supplements
Should you take inositol for PCOS lean type? Well, it depends. Since women with lean PCOS also have an increased risk for insulin resistance, inositol can have a positive effect on PCOS in lean women with insulin resistance. Additionally, it could help balance hormones, sugars and reduce inflammation (1).
In fact, insulin resistance affects 75% of women with PCOS and smaller bodies compared to 95% of women with PCOS and larger bodies (9).
So treating insulin resistance is an important part of managing lean PCOS and a supplement like inositol is a relatively safe option! Always chat with your dietitian and doctor before you add supplements, especially if you are on other medications.
Vitamin D supplementation has been shown to improve various factors in women with PCOS such as infertility, insulin resistance, blood sugar, and blood lipids, while decreasing facial hair growth and testosterone. Further, it may help increase the likelihood of successful IVF.
Women with PCOS should aim for 2000-4000 units of vitamin D daily via supplementation (7, 8). Read our blog on vitamin D and PCOS for more tips on the best way to take vitamin D.
Should Women Take Metformin For Lean PCOS?
Some research has shown that lean women with PCOS have been found to respond better to Metformin to control blood sugar, insulin resistance, and testosterone (1). However, the recent 2023 International Guidelines for PCOS state that this evidence is limited so this needs to be considered carefully by a physician as a part of the PCOS treatment plan (9).
Managing lean PCOS requires tailored treatment, but it’s essential not to dismiss symptoms because of a lower BMI. Symptoms like irregular periods, acne, hair growth, and weight gain may point to PCOS.
Making lifestyle changes such as incorporating low glycemic foods, exercising regularly, and getting good quality sleep can help control PCOS symptoms.
If you have lean PCOS and are struggling, talk to a PCOS expert like one of our Dietitians to create and support sustainable lifestyle changes that can optimize treatment. Start by reviewing our PCOS Nutrition Guide or take our PCOS Nutrition course!
Living with PCOS is tough, but you’re not alone. Take control of your health today!
(1). Toosy S, Sodi R, Pappachan JM. Lean polycystic ovary syndrome (PCOS): an evidence-based practical approach. J Diabetes Metab Disord. 2018 Nov 13;17(2):277-285. doi: 10.1007/s40200-018-0371-5. PMID: 30918863; PMCID: PMC6405408.
(2). Ding DC, Chen W, Wang JH, Lin SZ. Association between polycystic ovarian syndrome and endometrial, ovarian, and breast cancer: A population-based cohort study in Taiwan. Medicine (Baltimore). 2018 Sep;97(39):e12608. doi: 10.1097/MD.0000000000012608. PMID: 30278576; PMCID: PMC6181615.
(3). Barry JA, Azizia MM, Hardiman PJ. Risk of endometrial, ovarian and breast cancer in women with polycystic ovary syndrome: a systematic review and meta-analysis. Hum Reprod Update. 2014 Sep-Oct;20(5):748-58. doi: 10.1093/humupd/dmu012. Epub 2014 Mar 30. PMID: 24688118; PMCID: PMC4326303.
(4). Majumdar A, Singh TA. Comparison of clinical features and health manifestations in lean vs. obese Indian women with polycystic ovarian syndrome. J Hum Reprod Sci. 2009 Jan;2(1):12-7. doi: 10.4103/0974-1208.51336. PMID: 19562068; PMCID: PMC2700686.
(5). Simmonds MJ, Milne N, Ong K, Brotherton E, McNamee AP, Horobin J, et al. Physical properties of blood are altered in young and lean women with polycystic ovary syndrome. PLoS One. 2016;11:e0167290.
(6). Satyaraddi A, Cherian KE, Kapoor N, Kunjummen AT, Kamath MS, Thomas N, Paul TV. Body composition, metabolic characteristics, and insulin resistance in obese and nonobese women with polycystic ovary syndrome. J Hum Reprod Sci [serial online] 2019 [cited 2022 Oct 21];12:78-84. Available from: https://www.jhrsonline.org/text.asp?2019/12/2/78/260501
(7). Barrea L, Frias-Toral E, Verde L, Ceriani F, Cucalón G, Garcia-Velasquez E, Moretti D, Savastano S, Colao A, Muscogiuri G. PCOS and nutritional approaches: Differences between lean and obese phenotype. Metabol Open. 2021 Sep 13;12:100123. doi: 10.1016/j.metop.2021.100123. PMID: 34622189; PMCID: PMC8479825.
(8). Várbíró S, Takács I, Tűű L, Nas K, Sziva RE, Hetthéssy JR, Török M. Effects of Vitamin D on Fertility, Pregnancy and Polycystic Ovary Syndrome-A Review. Nutrients. 2022 Apr 15;14(8):1649. doi: 10.3390/nu14081649. PMID: 35458211; PMCID: PMC9029121.
(9). Teede, H. J., Tay, C. T., Laven, J. J. E., Dokras, A., Moran, L. J., Piltonen, T. T., Costello, M. F., Boivin, J., Redman, L. M., Boyle, J. A., Norman, R. J., Mousa, A., Joham, A. E., & International PCOS Network (2023). Recommendations From the 2023 International Evidence-based Guideline for the Assessment and Management of Polycystic Ovary Syndrome. The Journal of clinical endocrinology and metabolism, dgad463. Advance online publication. https://doi.org/10.1210/clinem/dgad463