Paleo or Primal Diet

Paleo is a simple dietary lifestyle that is based on foods being either in or out. In are the Paleolithic Era foods that we ate prior to agriculture and animal husbandry (meat, fish, shellfish, eggs, tree nuts, vegetables, roots, fruit, berries, mushrooms, etc.). Out are Neolithic Era foods that result from agriculture or animal husbandry (grains, dairy, beans/legumes, potatoes, sugar and fake foods).
Optimal Foraging Theory says our ancestors mostly ate foods that were easiest to hunt or gather at that specific locale. As nomads we would have adapted to various mixes of foods. Under the paleo concept the quantities consumed of each “in” food is up to the individual. You can make it meat heavy if you want, or more fruit and veggies if you prefer, as long as the foods you eat are paleo. Fruits in the Paleolithic would have been tart and smaller, and you may want to limit modern fruit because of this.
Acceptable oils should be restricted to those from fruits (olive, oil palm, avocado) or tree nuts (coconut, walnut, almond, hazelnut, pecan, macadamia). No high-tech industrial seed oils could have existed back then. Wild game meat would be the ideal, but grass-fed meat is used as a practical substitute. The grass-fed is needed to get the proper balance of Omega 3 (from green plants) and Omega 6 (from seeds) fatty acids. Organ meats and bone marrow are very paleo. No processed meats. Consumption of fat from grass-fed animals need not be restricted. See Gary Taubes's Good Calories, Bad Calories. Fish should be wild-caught. For everything else organic is preferred, as this is the best we can do to get food free of modern pollutants and with the original micronutrients.
The effort to collect most seeds would not be as optimal as collecting other foods, unless collected as a condiment for the seed’s taste. Some meaty seeds, like sunflower, may have been a food. To protect their reproductive cycle, plants put anti-nutrients in seed coverings to discourage animal consumption (phytic acid, lectins, and enzyme inhibitors). Fruit seeds are not supposed to be digested, but to pass through and still be viable. They would never have been a food.
Eat the greatest variety of foods possible. Bush hunters kill whatever they find moving. Foragers note that there are more than 300 edible plants that our ancestors would have known about. Many are leafy greens. A wide range of herbs and spices is encouraged.
Salt should not be added to food. They did not have salt shakers. After removing added salt from your diet your taste buds will lose the tolerance they developed for salt. The same thing happens after sweetness is removed.
The only beverage that is truly paleo is water. You need to drink only when you are thirsty. The best is spring water that has been certified to be free of pharmaceuticals, with no chlorine or fluoride added. Buy in large PET bottles. See report on: Pharmaceuticals lurking in U.S. drinking water. If you want caffeine, organic green tea is the most paleo. It is the least processed. Coffee is a seed inside a fruit and is not edible raw. Fruit juice is concentrated fructose that would not have existed and would not be paleo. A very paleo and healthy beverage would be coconut water.
Agave “nectar” is just the euphemistic marketing name for High Fructose Agave Syrup. It is highly refined and it should be avoided. The only paleo sweetener is raw honey, and only in limited quantities. You could argue that very dilute maple syrup is paleo. If you must have sweetness, another possibility is coconut palm sugar. But best is to get all sweets out of your diet and get over it.
The inclusion of alcohol in the paleo diet is controversial. Our paleo ancestors would have come upon and eaten fermented fruit. Even spurned male butterflies get drunk on fermented fruit. Some have issues with the yeast. In Wild Fermentation (p. 127 in Amazon.com's Look Inside) there is a recipe for spontaneous hard cider that requires no added sugar or yeast. Now the resulting product (6% ABV) does not last long, but it would be paleo! No published paleo diet includes alcohol. But if you are going to drink it, pick one from fermented fruit and water it down to 6%. Another paleo high would have been eating cannabis leaves.
Paleo foods are nutrient dense. Supplementation would not be needed, and would not be paleo. There is one exception: Vitamin D. At least it should be supplemented for those of us that don’t live outside year round, and don't eat liver regularly. See recommendations at the Vitamin D Council. If you don't eat fish often, fish oil is another way to get Omega 3 fatty acids, though some prefer krill oil.
Food should be eaten when hungry – not at set times of the day. They hunted and gathered foods in anticipation of, or in response to, hunger pangs.
This is also called the Caveman Diet, though there is little evidence that many of our ancestors actually lived in caves. Caves with paintings were only visited once a year. The name “Caveman Diet” implies a brutish character that thrived on meat. Stone Age Diet, besides sounding a bit old fashioned, is not correct. The Stone Age also covers part of the Neolithic. Hunter-Gatherer Diet is descriptive, but cumbersome. And other names are primal diet, ancestral diet, and evolutionary diet.