These findings are in line with another meta-analysis on 13 randomized controlled trials lasting at least six months comparing low-fat and low-carbohydrate diets. They noted that at six months, subjects who consumed less than 60 grams of carbohydrates per day had an average greater weight-loss of 8.8 lbs. compared to subjects on low-fat diets. [20] At one year, the difference had fallen to only 2.3 lbs. [20]
The findings below have been limited to research specific to the ketogenic diet: the studies listed contain about 70-80% fat, 10-20% protein, and 5-10% carbohydrate. Diets otherwise termed “low carbohydrate” may not include these specific ratios, allowing higher amounts of protein or carbohydrate. Therefore only diets that specified the terms “ketogenic” or “keto,” or followed the macronutrient ratios listed above were included in this list below. In addition, though extensive research exists on the use of the ketogenic diet for other medical conditions, only studies that examined ketogenic diets specific to obesity or overweight were included in this list. (This paragraph was added to provide additional clarity on 5.7.18.)

This research and other data indicate that olive oil is not heart protective, Dr. Robert Vogel told Pritikin Perspective. Dr. Vogel, a cardiologist who has studied heart disease for more than 30 years, counsels his patients to “feast on fish” and other rich sources of omega-3 fatty acids instead of olive oil, and to eat plenty of fruits, vegetables, and whole grains every day.
“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.”