Women with polycystic ovary syndrome (PCOS) have a considerable risk of metabolic dysfunction. This review aims to present contemporary knowledge on obesity, insulin resistance and PCOS with emphasis on the diagnostic and methodological challenges encountered in research and clinical practice. Variable diagnostic criteria for PCOS and associated phenotypes are frequently published. Targeted searches were conducted to identify all available data concerning the association of obesity and insulin resistance with PCOS up to September 2016. Articles were considered if they were peer reviewed, in English and included women with PCOS. Obesity is more prevalent in women with PCOS, but studies rarely reported accurate assessments of adiposity, nor split the study population by PCOS phenotypes. Many women with PCOS have insulin resistance, though there is considerable variation reported in part due to not distinguishing subgroups known to have an impact on insulin resistance as well as limited methodology to measure insulin resistance. Inflammatory markers are positively correlated with androgen levels, but detailed interactions need to be identified. Weight management is the primary therapy; specific advice to reduce the glycaemic load of the diet and reduce the intake of pro-inflammatory SFA and advanced glycation endproducts have provided promising results. It is important that women with PCOS are educated about their increased risk of metabolic complications in order to make timely and appropriate lifestyle modifications. Furthermore, well-designed robust studies are needed to evaluate the mechanisms behind the improvements observed with dietary interventions.

Intermittent fasting may impart metabolic benefits independent of energy balance by initiating fasting-mediated mechanisms. This randomized controlled trial examined 24-hour fasting with 150% energy intake on alternate days for 3 weeks in lean, healthy individuals (0:150; n = 12). Control groups involved a matched degree of energy restriction applied continuously without fasting (75% energy intake daily; 75:75; n = 12) or a matched pattern of fasting without net energy restriction (200% energy intake on alternate days; 0:200; n = 12). Primary outcomes were body composition, components of energy balance, and postprandial metabolism. Daily energy restriction (75:75) reduced body mass (−1.91 ± 0.99 kilograms) almost entirely due to fat loss (−1.75 ± 0.79 kilograms). Restricting energy intake via fasting (0:150) also decreased body mass (−1.60 ± 1.06 kilograms; P = 0.46 versus 75:75) but with attenuated reductions in body fat (−0.74 ± 1.32 kilograms; P = 0.01 versus 75:75), whereas fasting without energy restriction (0:200) did not significantly reduce either body mass (−0.52 ± 1.09 kilograms; P ≤ 0.04 versus 75:75 and 0:150) or fat mass (−0.12 ± 0.68 kilograms; P ≤ 0.05 versus 75:75 and 0:150). Postprandial indices of cardiometabolic health and gut hormones, along with the expression of key genes in subcutaneous adipose tissue, were not statistically different between groups (P > 0.05). Alternate-day fasting less effectively reduces body fat mass than a matched degree of daily energy restriction and without evidence of fasting-specific effects on metabolic regulation or cardiovascular health.

Coeliac disease (CD) is an autoimmune gastrointestinal disorder whereby the ingestion of gluten, a storage protein found in wheat, barley and rye, causes damage to intestinal mucosa with resultant malabsorption, increased risk of anaemia and osteoporosis. Worldwide estimates suggest 1% of the population have CD. With no cure, the only treatment is a gluten-free diet (GFD). Adhering to a GFD can be very challenging; it requires knowledge, motivation and modified behaviours. Assessing adherence to a GFD is methodologically challenging. This review aims to provide an overview of the literature reporting adherence to a GFD in people with CD and the methodological challenges encountered. From six studies it has been reported that rates of adherence to a GFD range between 45 and 90% in patients of different ethnicities with CD. GF dietary adherence can be influenced by age at diagnosis, coexisting depression, symptoms on ingestion of gluten, nutrition counselling, knowledge of GF foods, understanding of food labels, cost and availability of GF foods, receiving GF foods on prescription and membership of a coeliac society. To date only five intervention studies in adults with CD have been undertaken to improve GF dietary adherence. These have included dietary and psychological counselling, and the use of online training programmes, apps, text messages and telephonic clinics. Future interventions should include people of all ethnicities, consider patient convenience and the cost-effectiveness for the healthcare environment.

Treatment of coeliac disease requires a strict gluten-free (GF) diet, however, a high proportion of patients do not adhere to a GF diet. The study explores the practical challenges of a GF diet and dietary adherence in Caucasian and South Asian adults with coeliac disease. Patients with biopsy- and serology-proven coeliac disease were recruited from a hospital database. Participants completed a postal survey (n = 375), including a validated questionnaire designed to measure GF dietary adherence. Half of Caucasians (53%) and South Asians (53%) were adhering to a GF diet. The quarter of patients (n = 97) not receiving GF foods on prescription had a lower GF dietary adherence score compared with those receiving GF foods on prescription (12.5 versus 16.0; p < 0.001). Not understanding food labelling and non-membership of Coeliac UK were also associated with lower GF dietary adherence scores. A higher proportion of South Asian patients, compared with Caucasians, reported difficulties understanding what they can eat (76% versus 5%; p < 0.001) and understanding of food labels (53% versus 4%; p < 0.001). We recommend retaining GF foods on prescription, membership of a coeliac society, and regular consultations with a dietitian to enable better understanding of food labels. Robust studies are urgently needed to evaluate the impact of reducing the amount of GF foods prescribed on adherence to a GF diet in all population groups.