Different nutrition plans

I haven't started any conversation yet, so I'll try to focus attention on myself with several different thoughts. I'll appreciate if someone say his opinion and just correct me.

Recently I have read and observed more about nutrition. The Though most people around me don't follow any guidelines in their daily nutritional intake. Some of them are going to count their calories. But this is a big mistake, because in addition to this calculation there are many other factors like-the level otof metabolic rate (how well you absort the food) or the source, type and mirco/macronutirient in the food. In addition there are and next (here I want to say consequence from right these food intake, is there more accute word?) hormonal reactions (or factors). Because if you eat a chocolate only, your insulin (which is responsible for the aging process) and blood sugar level will increase, therefore you will gain weight (mainly fats) and all that will continue to happen until your cells will are starved for proteins (because protein is required for enegy ensure, enzyme producing and body recovery processes).
On the ohter other hand there are statements like- proteins will case you cancer or kidney diseases. I have read many pieces of researches and found that these statements  areis nothing more then manipulation of the statistics. There are many scientistics that agree with this too. The truth about it is that if you already have cancer, a high protein diet is bad for you, but otherwise it is very useful and beneficient. By analogy is for the kidneies. (?)
In last recent times there is a lot of are big interest about the fastings on a regular bias. I have heard only good things about it, but as well as we all know in the world there is not aren't something that is only positive. In fact I don't like it, because it can cause digestion problems and the benefits can be reproduced just by redusing proteins.
As my last points I want to mention about high fat diets. These diets were It go through taboo, but were then though to produce magic results get to something magic and now it's somewhere in the middle. I don't like high-fats diet at all (if you are interesting I'll recommend to watch the "Fat head" film, I think it was on BBC), because it escaped from all of the high carbs disadvantages such as developing insulin resistants, diabetes, metabolic syndrome, fat obeses, heart disease...) but also here we have to see the bigger picture and be careful, bacause our brain can use only carbohydrates as fuel and there are some bad types of fats.

I hope it was interesting for you and there aren't so many mistakes.
Best regards