Type 2 diabetes mellitus (T2DM) is a chronic disease characterized by high blood glucose and reduced insulin sensitivity. T2DM prevalence quadrupled from 1980 to 2014 and is projected to reach nearly 600 million cases by the year 2035. Obesity is considered the most important risk factor for the condition, accounting for about 90% of all T2DM cases, and patients generally display symptoms associated with metabolic syndrome and have an increased risk for cardiovascular disease.
While some drugs are available to help manage T2DM, lifestyle change (i.e., diet and exercise improvements) is preferred, as it is not associated with cardiovascular complications that accompany the use of some drugs, and has demonstrated improvements in insulin sensitivity and disease progression. The American Diabetes Association recommends the Mediterranean, DASH, and plant-based diets low in carbohydrates, saturated fats, and trans fats for weight loss in obese or overweight individuals who have or are at risk of developing T2DM.
Recent studies suggest diets high in monounsaturated fats can improve glycemic control. The monounsaturated fat content of the Mediterranean diet can be high enough to cover 25% of daily caloric intake and greater adherence to the diet reduces diabetes risk. A systematic review and meta-analysis of the literature found that the Mediterranean diet was associated with better glycemic control and cardiovascular risk factors than other diets, including a low-fat diet.
Still, there is no consensus on the best antidiabetic diet. Reductions in carbohydrate intake appear to improve T2DM management. When compared to a normal Mediterranean and American Diabetic Association diet, greater improvements in glycemic control and cardiovascular risk factors in a low-carbohydrate version of the Mediterranean diet have been reported. While a network meta-analysis, whose results are shown in FIgure 1, has previously compared different dietary patterns for glycemic control in people with T2DM, the authors of this study conducted a systematic review and network meta-analysis to investigate the efficacy of different dietary patterns on weight loss and cardiovascular risk factors in addition to glycemic control.
With type 2 diabetes prevalent and expected to affect close to 10% of the world population, targeting its most important risk factor of obesity through dietary intervention appears to be a good bet. While recommendations consist of plant-based diets low in carbohydrates and certain fats, there is no consensus on the best antidiabetic diet. The authors of the study under review aimed to investigate the best diet for improved glycemic control, cardiovascular risk factors, and weight loss.