I think calories matter to a certain extent. When I was losing weight I counted carbs, protein, fat, fibre and also calories. I had targets for all of them, all set out on a spread sheet as part of my food diary. I kept to 1200 calories, kept the carbs at my desired level and adjusted the protein and fats to keep within my calorie allowance. Once all my excess weight had gone, I increased the calories by again adjusting the proteins and fats but keeping the carbs low. Once I got the balance right, my weight stabilised. For me, personally, without counting the calories I would just have been guessing. The carbs may have been right for me, but my weight loss may have stalled. It didn't stall at all. Then when I needed to stabilise, calorie counting whilst keeping the carbs the same helped me stop losing and stabilise. I didn't do it for more energy, I did it for weight management. The good energy levels just happened.