I'll begin by saying that counting calories can be a great method to begin a transition into a healthy state. It could help someone who tends to overeat to ease back, or some who undereats to pick it up.
However, there is a huge misconception regarding calories and nutrition. There are those who believe that they can calculate their caloric requirements based on their own physical body, i.e. gender, weight, amount of exercise and this is exactly how much they need. Worse yet, there are those that believe that they need 2,000 calories per day, only a guideline given to use by the government.
Logically, we can reason why this is false. The ideal is to be able to tell how much food to eat based on feeling, once we have detoxified and learned to read our body correctly.
Someone who counts calories is totally disregarding the quality of food that they are eating. For example, one could get 2,000 calories in a single sitting just by eating a box of donuts. Does that mean that that they are good to go nutritionally?
That is extreme and obvious example, but then consider if one day you get most of your calories from grains and pasta. Cereal for breakfast, bagels and a salad for lunch, spaghetti for dinner. Is that the same as eating fruit for every meal? Which is easier to digest and assimilate, fruit or pasta? (a small bit of research will give you an obvious answer)
There are two more factors that affect how much food we need to eat:
1) The quality of the food.
2) Our ability to assimilate nutrients from that food.
You could even be eating the best food in the world, but if your digestive system is so messed up that you can't get all the nutrients out, then you still won't see great results. You might still have to eat much more to compensate for the waste. On the contrary, if you have begun the journey to health and healing, you might find that you require less food because of your body's growing efficiency in extracting the nutrients.
If you eat pizza for every meal one day and then fruit and salad for every meal the next day, do you really think that you will be getting all the nutrients out of the fruit? No! Your system is still in shock from all that toxic food the day before. And for that matter, most of it is probably still inside of you. Now consider a lifetime of poor and unnatural eating habits. How much are you really getting from the occasional "healthy" meal? Chances are that your ability to assimilate nutrients is so bad that yes, you might need a ton of calories every day.
The goal is to not eat too little or too much. Eat too little and you might not feel the best. However, overeating is equally bad if not worse, because then your body has to process all of that extra food, and that processing requires a great amount of energy! Some people think the more they eat the more energy they have. I used to think this, and it is just simply not true. It doesn't matter how high quality the food is. If you are filling your car up with gas, then it has a limit. Well, we have a limit too! Unfortunately, while the car will simply overflow, we MUST process that extra food.
If you are a healthy person then you do not need to eat that much. Human beings might be able to survive on large quantities of unnatural food, but we thrive on much smaller portions of fresh living foods. This doesn't mean that anyone can begin to cut down their portions and start feeling better. First you have to increase the quality of your diet by REMOVING the harmful foods and replacing them with fresh living foods. Then it might be a gradual process while your body heals and rebuilds its facility to efficiently process the food you eat.