PCOS and insulin resistance often occur together because insulin affects sex hormones, exacerbating symptoms such as irregular periods and excessive body hair. The right diet can help alleviate these problems - it's worth avoiding processed foods, looking after fibre, healthy fats and a low glycaemic index. There is no need to eliminate gluten, dairy or follow a ketogenic diet as there is no evidence of their effectiveness in treating PCOS. In addition to diet, physical activity, stress control and appropriate supplementation are important.