Strange ideas focusing only on carbs, protein, and fat are widespread

It seems like everyone is confused about what constitutes a healthy diet.
The idea that carbohydrates and fats are bad while protein is good, and so on.
If that were the case, people would just fill up on protein using processed meats like Spam, so why don't they?
Of course, the ratio of carbs, protein, and fat is important, but you must discard prejudices like "protein is unconditionally good" or "carbs and fats are unconditionally bad."
Furthermore, before calculating the ratio of carbs, protein, and fat, priority should be given to how much processed food and bad vegetable oils are present, and to what extent various sugars and additives are included.
The reason home-cooked meals are at least better than eating out is that you can use whole ingredients instead of processed foods and cook while minimizing bad oils, sugar, and flour.
This is why your health declines when you frequently consume delivery food or eat out.