The single most important factor in how much you weigh, in the long and short run, is the amount of carbohydrate you eat. The more carbohydrate you eat, the easier it is for your body to store fat. The more carbohydrate you eat, the hungrier you are. The more carbohydrate you eat, the higher your insulin and ghrelin levels, which drive fat storage. Calories count somewhat, we don’t know exactly how much. You’ll lose weight twice as fast on 1500 calories of protein and fat, compared to 1500 calories of carbohydrate. But if you take your protein and fat calories to stupid, you won’t lose weight. You cannot freeely feed on salad dressing, nuts, cheese, butter and high calorie meats, and expect to lose weight.