Thinking aloud, part II; crazy theories

Little something about diets.

According to many experts low-carb high-protein diets are bad for your health. I'd like to disagree a bit.
I've been thinking this quite some time and I've come to a conclusion that there is no such thing as one correct diet. I won't mix exercise in this theory now, so bear with me...

Have you ever noticed that there are people who have same diet, but person A stays/gets slim and person B gains/can't lose weight?
I've noticed that in myself. Every change in my diet has caused weight loss, that's for sure, but in the end none of them ever helped me to lose weight permanently. Or even keep in same weight for long.

Nutritionists recommend low-fat, high-carb diets as healthy. To everyone and that is where my thoughts get heretic.
When it comes to me I've noticed few things

1. I get arrhythmias when ever my diet is high-carb even for a day.
2. I get gout attacks for the same reason.
3. When I'm in high-carb diet I crave for sweetness, in other words I'm sugar rat when ever I'm 'healthy' diet which should provide me what my body needs.
4. I get depressed much more easily when I'm in high-carb diet.
5. I can't control my weight. If it decides to rise it'll, no matter what, and I can't keep my weight in balance.

I'm getting to a point, just wait a bit...

So, to me it seems that what is considered 'healthy' is not good for my body, or would you disagree? Now...
What if, and this is just one of my theories, there are people who benefit from high-carb diet and people who benefit from low-carb diet? And to high-carbers low-carbing would be as disastrous as high-carbing to low-carbers?

You know that disagreement of where first humans came from? Did they come from Asia or from Africa? What if... what if that explains the difference between suitable diets? Ethnicity may be the key. Just remember that we are all more all less mixed heritage.

Why I came to this conclusion? I've met quite a few persons who benefit from low-carb diet, myself being one of them. I've also met people who benefit from high-carb diet. And I can't believe that there's nothing behind that difference. I believe in reasons.