They didn't test a low fat diet in the study. 30% of calories from fat is not low fat. Also, it appears they used low saturated fat (<7%) and high PUFA. That's

They didn't test a low fat diet in the study. 30% of calories from fat is not low fat. Also, it appears they used low saturated fat (<7%) and high PUFA. That's pretty much backwards as it's well known that PUFAs have antimetabolic effects. All these experiments ever confirm (over and over) is that plenty of protein is helpful in the context of a reduced calorie diet, and that restricting food choices results in spontaneous calorie reduction. Protein has very high satiety and thermic effect. As for low fat or low carb it doesn't matter much. It's just that carbs and fat go great together and it's very difficult to overeat without the combination. A plain stick of butter and a large bowl of plain white rice are equally difficult to overeat on, whereas ice cream with its combined hit of sugar and fat is easy to gorge on.