Have PCOS and Not losing weight? It could be your GI

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Do you have Polycystic Ovary Syndrome (PCOS) and are struggling to lose weight? You’re not alone. As many as 80% of women with PCOS are overweight. The reason? High insulin levels, the central cause of PCOS. When insulin levels are high, it causes our bodies to store fat, usually in our bellies. Weight loss is difficult because it’s hard to break down fat if your body is in fat storage mode. In order to lose weight, you have to lower your insulin levels. You can lower insulin by diet, exercise and insulin-lowering medications (metformin) and supplements (Ovasitol). If you have been taking insulin sensitizers and are exercising and watching your diet and still aren’t seeing results it could be the types of foods you are eating.

Low Glycemic Index Diet for PCOS

Studies show individuals with high insulin levels do best as far as weight loss and improving insulin sensitivity on a low GI diet and this is especially true for women with PCOS.

A 2010 study compared a low glycemic (GI) index diet to a regular, healthy fiber diet in women with PCOS. Ninety-six women with PCOS were split into two groups: one group followed a low GI diet; another a high fiber diet that included whole grains. Both groups ate the same amount of calories and consumed the same distribution of macronutrients (50% carbohydrate, 23% protein, 27% fat, 34 grams fiber). The only difference was the glycemic index of foods.

Results: The women with PCOS who followed the low GI diet showed a 3-fold greater improvement in insulin. Women who followed the low GI diet and took metformin showed the best improvements in insulin sensitivity.

Other studies have shown that individuals with high insulin levels do best as far as weight loss and improving insulin sensitivity on a low GI diet. A study published in the Journal of the American Medical Association in 2007 showed that individuals with high insulin lost significantly more weight (13 pounds vs. only 3 pounds) following a low GI diet than those with high insulin levels who followed a low fat diet.
Another great benefit: women with PCOS who followed the low GI diet also had more regular periods (95% compared with 63%).

These studies show that insulin secretion is an important factor in weight management. Individuals with high insulin levels can lose more weight and improve insulin and periods on a low GI diet.

What to Know About the Glycemic index Diet

The glycemic index (GI) is a ranking of carbohydrates on a scale from 0 to 100 according to the extent to which they raise blood sugar levels after eating. Foods that fall under the high GI category cause surges in blood insulin soon after eating them. Foods categorized as medium GI cause mild changes and low GI foods cause the smallest increase in insulin.

Low GI foods


Medium GI foods


High GI foods

70 or more

Factors Influencing GI Ranking:

  • Type of Starch
  • Physical casing (intact grains have lower GI)
  • Fiber content  (soluble fiber lowers the GI)
  • Sugar content (sugar increases GI)
  • Fat and protein content slows GI
  • Cooking methods (cooking soften foods, increasing starch content and GI)
  • Acid content (more acidic foods have lower GI)
  • Food processing (processed foods have higher GI)

With this ranking, whole grain foods can be low, medium or even high GI versions. For example, All Bran has a GI value of 38 whereas the value of Cheerios is 74. See the GI value of your foods by viewing the complete GI data base: http://www.glycemicindex.com. Besides looking at low GI foods, it’s also important to consider their glycemic load based on the portion size of that food. Eating moderate amounts of low GI foods (think 1/4 of your plate) can be helpful to keep insulin levels down.

Tips For Eating Low GI

  • Replace refined foods with low GI or whole foods (unprocessed, grain intact)
  • Eat unprocessed breakfast cereals (bran, oats, barley)
  • Replace white potatoes with sweet potatoes
  • Avoid sugary foods and beverages
  • Include protein and/or fat in meals and snacks (nuts are a great example)
  • Cook pasta only until al dente (firm, not mushy)

Looking for low GI PCOS-Friendly Recipes? The PCOS Nutrition Center Cookbook has 100 Easy and Delicous Whole Food Recipes to Beat PCOS! 

pcos cookbook

Marsh K, et al. Effect of a low glycemic index compared with a conventional diet on polycystic ovary syndrome. Am J Clin Nutr 2010;92:83-92.

Ebbeling C, Leidig MM, Feldman HA, Lovesky MM, Ludwig DS. Effects of a low-glycemic load vs low-fat diet in obese young adults. JAMA. 2007;297:2092-2102.


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Comments (8)
  • Michelle

    November 12, 2014 at 10:26 am

    I’ve heard that whole grains raise insulin longer than refined grains. For example, whole grain bread or oats might have a lower GI but they might keep insulin high for a longer period of time since it’s so hard to break down. Whereas if someone ate white bread their insulin would shoot up quickly then go back down quickly. Have you heard this? I’ve actually found that whole grains make me anxious and jittery, whereas modest amounts of refined grains (like white bread) are fine if I treat them like a condiment… so I’m kind of confused 😉 Is it different for everyone?

  • Angela Grassi

    November 28, 2014 at 10:26 am

    Both the GI and the glycemic load, which focuses on portion size are important to consider. Everyone has a different insulin and glucose response to carbohydrates due to differences in meal timing, metabolic issues, and food preparation. Insulin has to increase in response to food intake. In general, low GI carbs don’t spike insulin but emit a slow and steady insulin response. It’s good you are tuned in to how your body responds to high vs. low GI foods and are limiting your intake of high GI foods.

  • Emerita Lovato

    November 28, 2014 at 10:26 am

    Nice tips, insuline spikes are affected by many factors, im getting spiked, when i do high carb, and high fat, when i go down with fat, everything looks perfect.

  • Angela Grassi

    December 28, 2014 at 10:26 am

    Not all carbohydrate foods are created equal, in fact they behave quite differently in our bodies. The glycemic index or GI describes this difference by ranking carbohydrates according to their effect on our blood glucose levels. Choosing low GI carbs – the ones that produce only small fluctuations in our blood glucose and insulin levels – is the secret to long-term health reducing your risk of heart disease and diabetes and is the key to sustainable weight loss. Eating too many carbs at once, even if low GI, can raise insulin levels. Everything in moderation!

  • Amy

    January 28, 2015 at 10:25 am

    So what would be better the glycemic index or the glycemic load diet? Or would it just be better to go gluten free first?

  • Pamela Pelletier

    March 17, 2015 at 10:25 am

    I’ve found a LOT of recent research pointing towards Gluten being an issue re: PCOS and infertility. I know many women (including myself) who have gone Gluten free and experienced a number of benefits. Many are recommending GF before low GI….what do think about this?

  • Angela Grassi

    January 28, 2016 at 10:25 am

    Yes, gluten can be an issue for some women with PCOS, especially if they have Hashimotos or other autoimmune diseases, but all women with PCOS do not need to eat gluten-free. Check out our post about gluten here. Some women do have a gluten intolerance. The only way to know is to try a strict gluten-free diet for 6 weeks or longer to see if you see any improvement in GI or PCOS symptoms. If done correctly (avoiding high sugar foods), going gluten free can offer many benefits, including improved fertility. The good news: many low GI foods are gluten-free too -quinoa, brown rice, some oats-so it’s possible to have benefits from both diets.

  • Medsides.Com

    March 11, 2020 at 8:02 pm

    Firstly, it’s important to remember that although PCOS is related to our hormone levels, and insulin production, it’s not your ‘fault’ if you have it. The symptoms can sometimes, however, be managed and hopefully, improved through diet and exercise.

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