Appropriate Intervention Diets to Manage Type 2 Diabetes Mellitus Among Adults in Australia: A Systematic Review.

Type 2 diabetes mellitus (T2DM) is a chronic metabolic disorder characterised by insulin resistance and hyperglycaemia, contributing to significant morbidity and mortality worldwide, including in Australia. This systematic review aimed to explore the most appropriate dietary interventions for managing T2DM among Australian adults. Following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, databases including PubMed, Medline, Embase, and Google Scholar were searched for studies published between 2010 and 2025. Eligible studies involved Australian adults with diagnosed T2DM and evaluated the effects of low-carbohydrate, Mediterranean, vegetarian, vegan, or intermittent fasting (IF) diets on glycaemic control, weight management, and diabetes-related complications. Thirteen studies, comprising randomised controlled trials, meta-analyses, and systematic reviews, met the inclusion criteria. Findings indicated that low-carbohydrate diets effectively improved glycaemic control and reduced HbA1c and fasting glucose levels. The Mediterranean diet showed strong evidence for improving glycaemic parameters, enhancing cardiovascular health, and reducing insulin resistance. Vegetarian and vegan diets improved insulin sensitivity and glycaemic control due to high intake of fibre, antioxidants, and unsaturated fats, while IF demonstrated modest benefits in HbA1c reduction and weight loss. Overall, all five dietary interventions were beneficial for T2DM management, but the Mediterranean and low-carbohydrate diets showed the most consistent and sustained improvements in metabolic outcomes. These findings support integrating dietary modification into diabetes care programs in Australia. Further research is warranted to determine long-term adherence, safety, and the optimal dietary approach for individualised management of T2DM.