So a bit after I started polysleeping, I started reading health blogs and stuff. Wanted to be sure I wasn't harming myself unnecessarily. Some of the stuff I've found out is not surprising:
* Fructose is really, really bad for you-- your liver stores it directly as fat, and it interferes with leptin, a hormone your fat cells make which tells your brain you're full. So it makes you fat *and* hungry. High fructose corn syrup gets demonized already. It's 55% fructose. Table sugar is... *drumroll* 50% fructose. Not a very big difference. So, sugar in general is terrible for you.
* Trans fats are extremely bad for you. (Why do they taste so good? Because they mimic saturated fats. See the next list.)
The rest of what I've found is completely shocking to me.
* Grains, wheat especially, are not good for you.
* Whole grains aren't much better than refined grains. Whole grains have more nutrients, but they also have more phytic acid, which binds with minerals and makes them unavailable to your body.
* Saturated fat is good for you. Yes, you heard that right. Butter, lard, tallow, coconut oil & palm oil. The fatty parts of your steak. Ground beef with 20% or more fat. Your body needs this fat.
* Fiber is not really necessary.
* Your teeth have the capability to heal cavities (provided you consume all the necessary nutrients).
* Meats are very good for you. Your digestive system is optimized for meat consumption.
* Vegetables do not contain anywhere near as much bio-available nutrition as does meat.
* Vegetable oils are bad for you. Including Canola (modified rapeseed oil), sunflower, safflower, corn, etc. They have way too much omega-6 PUFA (polyunsaturated fatty acids) and little to no omega-3.
* Exercise burns calories, but it also makes you hungry. So hungry that you're very, very likely to eat the calories to replace what you burned.
* Carbohydrates are not very good for you. Carbohydrates, all of them, turn into glucose in the bloodstream.
Your body normally needs glucose in the bloodstream equivalent to about a teaspoon of sugar. High blood glucose (BG) will do a lot of damage to your body (just ask any diabetic). So, after you eat your cereal, bread, potatos, pasta, or any sugary thing, your pancreas senses rapidly rising BG and dumps insulin into your blood. Insulin is a hormone that tells your body, "Get this glucose the **** out of here." Your body responds by storing the glucose. Many tissues respond. Muscle responds by storing the glucose as glycogen, which it will burn for energy later. Unless it doesn't have room. One tissue in your body always has room; you guessed it, your fat cells. Insulin tells them to store fat. (If your fat stops listening to insulin, then you're diabetic.) It gets worse though-- after the insulin spike, your BG may drop below the body's preferred level. Low BG makes you feel week and urgently hungry.
So, carbs -> sugar -> rising BG -> insulin -> store as fat -> low BG -> hunger. This is how Americans get fat.
Just the taste of sweetness can cause your body to produce insulin in anticipation of a crapload of glucose being dumped into your bloodstream. This is (perhaps) why diet sodas cause as much or more weight gain as regular soda in studies.
And, oh yes, you're screwed. Sugar might be more addictive than cocaine. When given a choice, rats choose to push the sugar-water button instead of the cocaine button.
This post is just an overview. I may elaborate and give references on this stuff in the future. It seems so much is wrong with the common knowledge that it's hard to even know where to start. I really can't believe it. I've been reading up on this for months now.
People in America really do listen to the government's recommendations. We've been eating less saturated fats and more carbs, especially grains like we're told to. We've been exercising more. And we've been getting fatter and less healthy. The guidelines are totally wrong.
This stuff is starting to get out. 100 years from now, our current mainstream wisdom will seem as wrong as bloodletting sick people does.
I started a paleo/low carb type diet (just wanting to be healthier, not to lose weight) soon after I started reading about this stuff. Within 24 hours I felt way better, mostly because the wheat got out of my system. Turns out I feel like crap when I eat wheat. That's a bummer, because I really like bread. This is a good random place to end this post.