I've been obsessing over nutrition the past month, so I'll share some of my findings...
Best diet (from all my findings so far) you can do for your health is high carb, low fat, low protein. The ratio to aim for is 80/10/10 (meaning 80% of your caloric intake from carbs, 10% fat, 10% protein).
You wanna get ~5g of carbs for every 1 lb of bodyweight. Carbs are important because they're what give you energy... your body really doesn't utilize that much protein and most of it gets converted to carbs. So it's inefficient for your body to waste energy converting them to carbs, you might as well just eat them.
From what I understand, eating too much protein also isn't good either because the conversion process creates side products that aren't good for the body, but I don't know a lot about this yet.
The best source of carbs is fresh ripe raw organic fruit, hands down. They're the most easily digestible and assimilated food out there.
So the best way to eat is a raw vegan low fat diet, consisting of mainly of fruit and then you wanna get 2-4% of your calories from leafy greens.
Of course it takes some major will power to get yourself to eat that way, but if you're extremely dedicated and have goals in mind, it's doable.
I know all this is going to sound completely contrary to everything you've learned, but I'm trying to really dig deep into the subject. I'm planning to do more research, but this is just what I believe right now.
If you wanna know more, these two books are a good starting point:
The China Study
The 80/10/10 Diet