Neckhammer, I frequently make two points around here:
1.) If you are losing weight on your diet, it's not due to fat count, carb count, macro skewing, etc. You are simply burning more energy than you are consuming.
2.) For the vast majority of people, they will diet down best and most healthfully on a mix of all macronutrients and not treating one as the enemy.
This study suggests one of two things: there is either no metabolic advantage to a ketogenic diet versus a mixed diet of equal calories, or a slight disadvantage.
I don't like ketogenic diets for the majority of the population because they are not ideal for the majority of the population. A mixed diet is going to preserve lean mass the best, you're going to have the most exciting meals due to the wide array of foods available to you and you'll be least likely to develop any nutrient deficiencies or metabolic issues because you will have a more varied diet. If a ketogenic works best for you, it is probably because the food is relatively boring by comparison so you just don't eat as much. But the success of a diet shouldn't be measured solely in terms of weight loss, either.
Now, you have to use some common sense. A baked potato covered in cheddar cheese, bacon and green onions may be perfectly Primal on paper...but that's kind of easy to overeat. That's not the fault of the starch in the potato. That's not the fault of the fat in the bacon or cheddar. You just have to be responsible. And this is what I recommend: responsible, balanced dieting using whole foods.