A study of 89 obese adults who were placed on a two-phase diet regimen (6 months of a very-low-carbohydrate ketogenic diet and 6 months of a reintroduction phase on a normal calorie Mediterranean diet) showed a significant mean 10% weight loss with no weight regain at one year. The ketogenic diet provided about 980 calories with 12% carbohydrate, 36% protein, and 52% fat, while the Mediterranean diet provided about 1800 calories with 58% carbohydrate, 15% protein, and 27% fat. Eighty-eight percent of the participants were compliant with the entire regimen.  It is noted that the ketogenic diet used in this study was lower in fat and slightly higher in carbohydrate and protein than the average ketogenic diet that provides 70% or greater calories from fat and less than 20% protein.
You'll find lots of free Mediterranean diet resources on the Oldways website, including an easy-to-understand food pyramid; a printable grocery list; gender- and age-specific tips on making the Mediterranean switch; a quick-read "starter" brochure; a recipe newsletter; and even a glossary defining Mediterranean staples, from bruschetta to tapenade.
In fact, the FDA now allows olive oil labels to carry the claim that its monounsaturated fat can reduce heart disease risks -- with a few strings attached. The claim says that "limited and not conclusive scientific evidence" suggests that eating about 2 tablespoons of olive oil daily may reduce the risk of heart disease. To give this possible benefit, it adds, the olive oil must replace a similar amount of saturated fat in your diet -- and must not increase the total calories you eat in a day.