I’ve heard many people state with certainty that the number of calories you eat on a low carbohydrate diet doesn’t matter. I believed this to be true myself in the beginning. My initial experience was that I was losing weight on 1800-2000 calories per day, which was approximately how much I had been eating before - and gaining weight! What I failed to realize was that on average I had started to eat less: Those uncontrolled binging sessions where I inhaled half a kilo of lollies or chocolate had come to an end (for the first time in my life!). And I think this is true for most people.
I still believe the old “calories in minus calories out” to be true. But the reason a low carb diet works is that it so efficiently allows you to control your calorie intake – without having to worry about counting those calories.
By the way, a low carb diet can be so many things. When you cut the carbs you need to replace them with something. Adding lots of protein isn’t as efficient as replacing the carbs with more fats (think avocado, nuts, full fat sour cream, sauces made from butter, full fat cream etc). The reason is that excess proteins are converted to carbs in our bodies, leading to the increased insulin and thereby fat storage that we are trying to avoid in the first place by eating low carb.