A meta-analysis of 13 randomized controlled trials following overweight and obese participants for 1-2 years on either low-fat diets or very-low-carbohydrate ketogenic diets found that the ketogenic diet produced a small but significantly greater reduction in weight, triglycerides, and blood pressure, and a greater increase in HDL and LDL cholesterol compared with the low-fat diet at one year.  The authors acknowledged the small weight loss difference between the two diets of about 2 pounds, and that compliance to the ketogenic diet declined over time, which may have explained the more significant difference at one year but not at two years (the authors did not provide additional data on this).
So is the Mediterranean diet still healthy? Absolutely. While this one study may have been flawed, it doesn’t change the fact that fresh fruits, veggies, lean proteins, whole grains, fish and healthy fats like olive oil (along with the occasional glass of wine!) are all foods that are proven to be good for you on their own. Together, they comprise a diet that can be terrific for your health — study or no study.
Cold pressed extra virgin olive oil has many benefits when used properly. You may not want to cook with it at high temperatures, though. While it appears to be more stable than other vegetable oils, all oils break down and lose their nutrients and flavor when cooked on high heat. Plus, the oxidation that happens during cooking may actually create compounds that attack healthy tissues in the body. For cooking at extremely high temperatures, it may be advisable to use a more stable fat that’s a shorter chain fatty acid, like coconut oil or avocado oil.
“The general body of research says that once you have two or more tablespoons a day, you’ll improve your blood pressure, your glucose levels and your good cholesterol,” Flynn says. “But I’ve found that the weight-loss effect comes into play at three tablespoons, so that’s what I recommend. It’s an amazing food – it does all these things that help your body, plus it tastes good.”