This is a general nuts and bolts version of what the Paleo Diet is all about. If you want to have a more in depth explanation about the Paleo diet along with a bunch of medical proof then i urge you to read "The Paleo Diet," by Dr. Loren Cordain. It is extremely informative and you will get more information about the diet than you really need.
To start, the Paleo Diet is the technically the oldest diet out there. It is the diet of out Ancient ancestors who roamed the land looking for animals to hunt and fruit and nuts to gather. We did this for tens of thousands of years and during this time, our ancestors were generally very healthy people. Their bones were dense and healthy, their hearts were strong, and their teeth were white. It wasn't until the agricultural revolution that we really started to turn into the fat and unhealthy people that we are today. The most elite athletes swear by it as do former obese and overweight people as a lifestyle to get healthy and happy.
The rule to follow: Don't eat any grains. Don't any Legumes (beans). Eat lean grass fed meat, fruit, nuts, and seeds.
They say that you shouldn't eat any grains is because it is high in carbohydrates which is a more or less a sugar. That's why diabetics are encouraged to stay away from high carbohydrate foods because it will negatively effect their insulin levels. When you eat a bowl of pasta, you are effecting your insulin and that causes you to store fat. One other aside, what do you think cows eat to get them fattened up: Grains. Corn is a grain and a sugary one at that. So next time you sit down to a bowl of pasta, you are pretty much doing the same thing as the cows are doing to get that good marbling in the meat.
Your not supposed to eat legumes because on their own they are poisonous. They are only safe to eat when fully cooked.
The reason why it is so good to eat grass fed beef because #1 It is more filling than grains. If you think that I'm wrong try to eat a half a pizza, then compare it to eating a 12oz steak. The steak will fill you up much more or as much as the half a pizza and has less calories, and more nutrients. #2 Grass fed Beef gives you a plethora of nutrients that aren't found in your Wal-Mart steaks. The reason for this is because the cows are free to roam around and eat all the grass. The grass is filled with nutrients, unlike corn.
The carbohydrates that are found in fruits and veggies are so minimal, and the nutritional value of them far exceed what you would find in the same amount of grain. There are no anti-oxidants in grains for instance.
Fats from nuts are extremely good for you. Anyone that tells you that fats will make you fat, is lying to you. What makes you fat is excessive carbohydrates. If fact, the only way that you can really lose fat is to ingest small amounts of it. If you body doesn't know how to handle fats that come into it, how is it going to know how to take care of fats that are already there?
ok so the Rule of Thumb: Stick to the outside of the supermarket. Don't eat anything that has been processed. Don't Eat Grains, Don't Eat Legumes, and keep dairy products to a minimum.
For more information please check out Loren Cordains book. It's worth the read.
PS I have lost 20 lbs since being on the paleo diet.