Benefits of a Low-Carb Diet for PCOS

Women with polycystic ovarian syndrome (PCOS) often have insulin resistance or diabetes. Insulin resistance is a condition where the cells in the body do not properly respond to insulin, resulting in high blood sugar and diabetes.

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Research shows women with PCOS can benefit from following a low-carbohydrate or low-glycemic index (GI) diet, which can aid in managing weight loss and reducing the risk of diabetes.

More Regular Periods

A 2010 study published in the American Journal of Clinical Nutrition found that women with PCOS who followed a low-GI diet had better insulin sensitivity, more regular menstrual cycles, and higher quality of life scores than women who didn't.

The study included 96 women aged 18 and 40, who were diagnosed with PCOS. Women who were taking metformin were still eligible, though women who had diabetes or depression were excluded from the study.

The women were assigned to follow either a low-fat, low-GI carbohydrate diet (50 subjects) or a low-fat, healthy diet with moderate to high GI carbohydrates (46 subjects). Subjects were followed for one year or until they lost 7% of their body weight.

While all participants reached their weight loss goal, 41% of the low-GI dieters and 50% of the regular GI dieters failed to reach that goal within the specified one-year goal. Women who took metformin in addition to following a low-GI diet had significantly higher improvements in their glucose tolerance testing as well.

Weight Loss and Improved Insulin Sensitivity

A 2015 study in the Journal of Obesity and Weight Loss Therapy found that women with PCOS who follow both a low-starch and low-dairy diet were better able to lose weight, improve their insulin sensitivity, and reduce testosterone levels.

The study included 24 women who were overweight or obese who followed a diet low in carbohydrates and dairy products for 8 weeks.

At the end of the study, the women lost an average of 19 pounds, reduced their body mass index, and lost about 3 inches from their waist circumference. In addition, the women saw a reduction in insulin levels and insulin resistance measures, as well as a reduction in testosterone levels.

The researchers noted that while carbohydrates are the main stimulators of insulin release, dairy products and starches result in higher post-meal insulin secretion than non-starchy vegetables and fruits. In addition, high levels of insulin are believed to increase androgen levels in women with PCOS.

Body Mass Index

The most commonly used measure to correlate weight and height is the body mass index (BMI). It uses weight and height to try and estimate body fat. The resulting number is then used to categorize people as underweight, normal weight, overweight, obese, or morbidly obese. BMI is not perfect, however, and does not account for other factors that determine body composition like age, muscle mass, or sex. BMI calculations may, for example, overestimate body fat in athletes or in older people. Additionally, BMI can also stigmatize and shame people who do not meet what is considered an ideal weight or body shape.

3 Sources
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  2. Phy JK, Pohlmeier AM, Cooper JA, et al. Low starch/low dairy diet results in successful treatment of obesity and co-morbidities linked to polycystic ovary syndrome (PCOS)J Obes Weight Loss Ther. 2015 Apr;5(2):259. doi:10.4172/2165-7904.1000259

  3. Gutin I. In BMI We Trust: Reframing the Body Mass Index as a Measure of Health. Soc Theory Health. 2018;16(3):256-271. doi:10.1057/s41285-017-0055-0