Calories are King!
There are many diets that promise weight loss, even the Twinkie Diet. The Ketogenic diet has been a diet popularized by many for it's ability to increase body fat loss in comparison to other diets. In this very recent study, it was shown that a Ketogenic Diet (KD) slowed fat loss, increased protein utilization, and increased muscle loss. However, the biggest take away from the study was that in a hypocaloric diet (reduced calories comparative to baseline), whether high carb or low carb, weight loss occurred. To expand further on this concept, Dr. Mike Israetel in The Renaissance Diet notes,
The more carbs that are consumed, especially on a hypocaloric diet, the more energy there is for training, the more insulin there is for anabolic stimulus, and the more glycogen there is for future intense training, recovery, and anabolism.
In the video below, Dr. Mike Israetel goes over KD and how it relates to an athlete's performance and recovery. Carbohydrates greatly increase performance and recovery.
Understanding calorie intake is fundamental in your eating habits. We have to learn to add and subtract before we try our hand at integrals and differential equations. To lose weight, maintain, or gain weight is about the amount of calories taken in. If you eat "clean" but gain weight or can't lose weight, don't blame the foods, blame the amount.