The Mediterranean diet is consumed in regions that border the Mediterranean Sea. Epidemiological studies show that it contributes to better health and overall quality of life. It is also an established model of eating for primary and secondary prevention of various chronic diseases. The Mediterranean diet consists of a variety of fruits, vegetables, cereals, legumes, poultry, fish, nuts, seeds, olive oil, and moderate intake of red wine with meals ⁽¹⁾. Olive oil, a monounsaturated fatty acid (MUFA), comprises 15% to 20% as the major source of dietary fats in this diet ⁽²⁾. Another hallmark is the low consumption of meat and dairy products ⁽³⁾.

Epidemiological analyses suggest that over 90% of type 2 diabetes, 80% of coronary heart disease, and 70% of stroke can be avoided by adopting healthful food choices that model the traditional Mediterranean diet ⁽⁴⁾.

Although there were no significant associations with reduced bladder cancer risk ⁽¹¹⁾, other large prospective studies found that adherence to the Mediterranean diet resulted in significant reductions for hip fracture incidence ⁽¹²⁾, risk of sudden cardiac death ⁽¹³⁾, gastric adenocarcinoma incidence ⁽⁶⁾ , modest reductions in colorectal cancer risk ⁽¹⁴⁾, and overall reduction in cancer risk ⁽⁷⁾. A randomized controlled trial demonstrated that a Mediterranean diet can reduce the risk of cardiovascular  events ⁽¹⁰⁾. Conclusions of various meta-analyses also indicate associations between greater adherence to the Mediterranean diet and significant reductions in weight gain ^(15) (16) as well as risk factors for diabetes and cardiovascular diseases ^{(8) (9) (15)}, overall mortality, cancer incidence and mortality, and incidence of Alzheimer’s and Parkinson’s disease ⁽¹⁾. Results from PREDIMED, the largest long-term randomized trial in Spain examining disease and mortality outcomes with the Mediterranean diet, also confirm these findings ^{(17) (18) (19) (20) (21) (22)}. Moreover, secondary analyses of PREDIMED suggests that a Mediterranean diet supplemented with extra-virgin olive oil confers benefits in the prevention of breast cancer ⁽²⁹⁾, and improves atheroprotective functioning of high-density lipoproteins for individuals at high risk for cardiovascular disease ⁽³⁰⁾. Other studies suggest it can reduce systolic blood pressure, improve endothelial functioning ⁽³¹⁾, and protect against macular degeneration ⁽³²⁾.

Interestingly, a large cross-sectional study identified certain factors that improved adherence to the Mediterranean diet, including female sex, older age, higher levels of physical activity, and moderate alcohol consumption, while poorer adherence was associated with males and obesity ⁽²³⁾. However, these results may not be translatable to the general public and may be unique to the culture of the Spanish populations studied.

Cancer patients may have special nutritional needs and should consult a dietician before changing diet. Alcohol consumption can increase the risk of certain cancers ⁽⁵⁾.