A Mediterranean diet mainly consists of high consumption of vegetables, fruits, beans, olive oil, whole grains and fish.
Previous research has strongly suggested that there are numerous health benefits from following a Mediterranean diet. Late last year, a study suggesting that middle-aged women may have a longer lifespan and better health if they follow the diet, while another study suggests the diet may reduce genetic stroke risk.
According to the study investigators from Spain, research has shown that weight-loss interventions, such as a low-calorie diet, are effective for the prevention of diabetes.
But they note there is limited information as to whether changes in diet that do not lead to weight loss, or involve reduction in calories or increased exercise, have the same effect.
To find out, the researchers analyzed 3,541 men and women without diabetes aged 55-80-years-old who were at high risk for heart disease - a condition known to be a risk factor associated with type 2 diabetes.
All participants were randomly assigned to one of three diets. The first was a Mediterranean diet in which subjects were required to consume 50ml of extra-virgin olive oil each day. Some participants followed a Mediterranean diet alongside 30g of mixed nuts each day, while the remaining subjects followed a low-fat diet. During a 4-year follow-up period, the participants following the Mediterranean diet were given guidance by dietitians. They were instructed to increase consumption of fruits and vegetables, beans, and fish, and to avoid red or processed meat, butter and candies.
The investigators note that none of the subjects were told to reduce their calorie intake or increase their physical activity.
At the end of the follow-up period, the researchers found that 273 participants had developed diabetes. Of these, 101 were from the low-fat diet group, while 80 were from the Mediterranean diet group with additional extra-virgin olive oil, and 92 were from the Mediterranean diet group with extra nuts.
