Mediterranean diets, low-carb and low-fat diets

• In 2008 The New England Journal of Medicine published a 2-year trial in which 322 moderately obese subjects were placed on one of 3 diets: low-fat, restricted-calorie; Mediterranean, restricted-calorie; or low-carbohydrate, non-restricted-calorie. The low-carb and Mediterranean groups both lost more weight than the low-fat group and had more favorable lipid profiles as well as blood sugar and insulin levels. [Source]

Hypertension

• In 2004 Clinical Nutrition published a crossover study in which 31 hypertensive and 31 normotensive elderly volunteers consumed diets enriched in virgin olive oil or sunflower oil for 4 weeks each. Results showed that virgin olive oil was helpful in reducing hypertension in elderly subjects but not cholesterol. [Source]
• In 2012 the American Journal of Hypertension published a 24-subject, double-blind, crossover study which found that 8 weeks of a diet enriched with polyphenol-rich olive oil reduced blood pressure and improved endothelial function in women with early stage hypertension. [Source]