Popular Conditions & Diets
Dietary advice for polyendocrine metabolic ovarian syndrome (PMOS), formerly known as PCOS, often focuses heavily on carbohydrates. Low-carb and ketogenic diets are commonly recommended, particularly because insulin resistance is such a prominent feature of the condition.
There is evidence supporting carbohydrate restriction, but the research tells a more nuanced story. Low-carbohydrate diets can improve several metabolic and hormonal markers in PMOS, while diets containing considerably more carbohydrate have also produced benefits when those carbohydrates are higher in fibre and lower on the glycemic index.
For most people with PMOS, this means carbohydrates don't necessarily need to come off the menu. Carbohydrate quality and overall dietary pattern may be just as important as carbohydrate quantity.
The recent change from polycystic ovary syndrome (PCOS) to polyendocrine metabolic ovarian syndrome (PMOS) reflects a broader understanding of the condition. Rather than being an isolated ovarian disorder, PMOS involves interacting ovarian, endocrine and metabolic abnormalities. The new terminology also moves away from the misleading implication that ovarian cysts define the condition.
Insulin resistance is an important part of this picture. Normally, insulin helps glucose move from the bloodstream into cells where it can be used for energy. With insulin resistance, tissues become less responsive to insulin, and the body compensates by producing more of it, which can affect organs and tissues that produce hormones like testosterone.
Insulin resistance appears to be especially common in PMOS. According to the landmark 2026 Lancet consensus paper where the shift from PCOS to PMOS was formalized, around 85% of people with the condition experience insulin resistance and the higher insulin levels that tend to come with it, even about 75% of lean women. Those elevated insulin levels can affect more than blood sugar, potentially stimulating the ovaries to produce more androgens.
Improving insulin sensitivity is therefore an important consideration when managing PMOS. And because carbohydrates have the greatest direct influence on post-meal glucose levels, it's understandable that they've ended up under the dietary microscope.
Carbohydrates are a very big nutritional umbrella. Lentils are carbohydrates. So are oats, berries, white bread, pastries and soft drinks. Metabolically, however, these foods are hardly interchangeable.
This is where the glycemic index (GI) can be useful. It tells us how a carbohydrate-containing food affects blood sugar. The glycemic load (GL) adds another piece of the puzzle: how much carbohydrate you're actually eating.
Low-glycemic, fibre-rich foods such as legumes, vegetables, whole fruit and minimally processed whole grains therefore bring something quite different to the table than sugary drinks and refined baked goods. This distinction becomes particularly important when examining research on carbohydrates and PMOS.
Carbohydrate restriction does have evidence behind it. A meta-analysis of eight randomized controlled trials involving 327 women with PCOS found that lower-carbohydrate diets significantly improved BMI and HOMA-IR (a marker of insulin resistance), as well as total and LDL cholesterol. Longer interventions also improved FSH, SHBG, and testosterone.
It's important, however, to understand what "low-carb" meant in this research. The meta-analysis defined a low-carbohydrate diet as one providing less than 45% of macronutrient intake from carbohydrates. These were not necessarily ketogenic or very-low-carb diets.
That's an important bit of context, especially given how loosely the term "low-carb" gets used online. Reducing carbohydrate intake can therefore be a useful strategy, particularly when insulin resistance is present, but current evidence doesn't establish that severe carb restriction is required for managing PMOS.
Research examining the glycemic quality of carbohydrates provides another perspective- and some of the most interesting evidence in this area.
A systematic review and meta-analysis of 10 randomized controlled trials involving 403 women with PCOS compared lower- and higher-GI or GL diets. Lower-GI diets significantly improved HOMA-IR, fasting insulin, total and LDL cholesterol, triglycerides, waist circumference, and total testosterone.
Notably, body weight did not differ significantly between the lower- and higher-GI groups. That matters because it suggests that at least some of these metabolic and hormonal improvements may occur without greater weight loss.
One of the included trials illustrates this particularly well. Participants following a low-GI, pulse-based diet received approximately 52-55% of their calories from carbs, with an emphasis on low-GI, high-fibre foods like legumes. The comparison diet contained essentially the same proportion of carbohydrate but had a higher GI, higher glycemic load and less fibre.
More than half of their calories were still coming from carbs. What changed was the kind of carbohydrates they were eating. Findings like these give us good reason to look beyond the carb count alone.
Current research doesn't support one universally superior dietary pattern.
A 2024 systematic review and network meta-analysis compared 10 dietary interventions and metformin across 19 randomized controlled trials involving 727 women with PCOS. The DASH diet ranked highest for reducing HOMA-IR, fasting blood glucose, fasting insulin and triglycerides. Low-calorie diets performed best for BMI, while low-carbohydrate diets ranked highest among dietary interventions for reducing total cholesterol.
Interestingly, DASH isn't inherently a low-carbohydrate diet. It emphasizes vegetables, fruit, whole grains, legumes, nuts and other minimally processed foods.
The available evidence, therefore, points toward several viable approaches rather than a single prescription. Someone may do well with moderately lower carbohydrate intake, while another person may consume considerably more carbohydrate from high-fibre, low-GI sources and still improve metabolic health.
There are, in other words, several roads to better insulin sensitivity.
A practical PMOS diet can begin by prioritizing protein, and follow through by making fibre-rich, minimally processed carbohydrates the default. Beans, lentils, vegetables, whole fruit, oats, quinoa and other whole grains provide carbohydrates alongside fibre and other nutrients.
Refined carbohydrates and added sugars can be consumed less often, particularly sugar-sweetened beverages, sweets, pastries and other foods that provide rapidly absorbed carbohydrate with relatively little fibre. This doesn't require treating a teaspoon of sugar like a metabolic emergency.
PMOS-healthy meals can also combine carb sources with protein, fibre and healthy fats for less insulinemic effect. Fruit can be paired with Greek yogurt or nuts, for example, while rice or another grain can form part of a meal containing vegetables and a substantial protein source.
Portion size still matters. GI describes how a carbohydrate food affects glucose, while glycemic load accounts for both GI and the amount of carbohydrate consumed.
Finally, food is only one part of the insulin-sensitivity equation. Physical activity, sleep, and stress management, along with dietary intervention, are critical as first-line management for PMOS symptoms.
Carbohydrates don't need to be eliminated simply because someone has PMOS. Research supports lower-carbohydrate diets as one option, but it also shows meaningful improvements with diets that retain substantial amounts of carbohydrate while emphasizing lower-GI, higher-fibre foods.
Rather than getting stuck on the question of whether carbs are "good" or "bad," a more useful approach is to consider carbohydrate quality, quantity and the overall composition of the diet. For many people, that means emphasizing whole-food carbohydrate sources, reducing refined carbs and added sugar, and finding an eating pattern that supports insulin sensitivity while remaining realistic enough to maintain in the long term.
Should I avoid sugar if I have PMOS? Sugar doesn't need to be completely eliminated. Limiting added sugars and highly refined carbohydrate foods is a reasonable strategy when the goal is to improve insulin regulation.
Do I need to eat low-carb if I have PMOS? No. Low-carb diets can improve several PMOS markers, but current evidence doesn't show that they're necessary or universally superior.
What are the best carbs for PMOS? Favour fibre-rich, minimally processed sources such as beans, lentils, vegetables, whole fruit and whole grains. These can provide carbohydrates while supporting a lower-glycemic dietary pattern.
What is the best diet for PMOS? There isn't currently one diet proven best for everyone. Low-GI, lower-carbohydrate and DASH-style approaches all have supportive evidence.
Is keto good for PMOS? The available low-carb evidence shouldn't be interpreted as evidence specifically for keto. In one major meta-analysis, "low-carb" was defined as less than 45% of macronutrient intake from carbohydrates.
Share this article
