In excess of 371 million people worldwide have diabetes. Diabetes prevalence is rapidly increasing in every country around the world. Australia has an estimated diabetes prevalence of 1.7 million with at least 1 undiagnosed case for every diagnosed case. It is the sixth leading cause of death, primarily from cardiovascular disease, and costs the economy approximately $35 billion dollars annually. More than half the cases of diabetes are preventable through diet and lifestyle changes, however rates continue to rise.
The worldwide diabetes epidemic is paralleled by the worldwide obesity epidemic and it is estimated that approximately 60% of diabetes cases could be prevented with weight loss, diet and lifestyle modification. However, intensive weight loss is not always the solution. The Look Ahead (Action for Health in Diabetes) study, a multicentre randomised clinical trial of 5145 overweight/obese people with type 2 diabetes (T2DM), investigated the impact of an intensive weight loss diet and exercise program compared with standard care on Cardiovascular (CVD) mortality and morbidity over 10 years. Disappointingly, at the 9.6 yrs follow-up there was no difference in CVD mortality or morbidity in the T2DM participants between the intervention and standard care, despite the intervention group losing weight and improving fitness. It is unclear why the intervention did not confer morbidity and mortality benefits, however the intervention was focussed on energy and fat restriction without a specific focus on diet quality.
A recent systematic review and meta-analysis of 20 RCTs involving more than 3000 participants examined the effects of 4 diets on management of T2DM (reduction in HbA1c, weight and increase in HDL) i) Low CHO, ii) Low GI, iii) High PRO, and iv) Mediterranean and found that the Mediterranean diet was effective in all 3 outcomes, whereas other diets were effective on single parameters only. Furthermore, the recent PREDIMED trial, a multicentre primary prevention trial of 7500 participants randomised to 2 Mediterranean diets (+olive oil or + tree nuts) or control, reported a 52% reduced risk of developing T2DM at 4 years.