An evidence-based assessment of the nutritional recommendations for the prevention of diabetes mellitus

There are accumulating levels of scientific knowledge concerning the dietary recommendations for the prevention of type 2 diabetes mellitus (T2DM). Purpose: This systematic review presents the most recent scientific knowledge concerning dietary recommendations for T2DM published in the English language by various scientific societies during the past 10 years. Methods: The recommendations are herein presented and discussed in the light of a critical, evidence-based appraisal aiming to provide a comprehensive guide for the clinician in daily practice. Results: In the case of overweight or obesity, the cornerstone of the primary prevention of T2DM is the combination of a healthy body weight (body mass index < 25 kg/m²) or a reduction of fat by at least 7% and the implementation of at least 150 min of moderate physical activity per week. Restriction of calories and of dietary fat is recommended, the latter as well as several dietary patterns providing a holistic approach to dieting and all having been correlated with decreased risk of T2DM. Among these dietary patterns are the Mediterranean diet, the DASH diet (Dietary Approaches to Stop Hypertension), the low-glycemic diet, and the HEI-Healthy Eating Index and AHEI-Alternative Healthy Eating Index. Micronutrient deficiencies of, for example, vitamin D, chromium and magnesium, may be associated with insulin resistance in T2DM. Conclusion: Overall, the combination of nutrition through dietary patterns that are mainly plant-based and which emphasize wholegrains, legumes, nuts, fruits, and vegetables and that include only small percentages of refined and processed foods, together with physical activity, has been associated with decreased T2DM risk.