A "hunter-gatherer" can be defined as a population that obtains their food directly from wild natural sources, including wild plant foods and game animals.1 Hunter-gatherers, also know as foragers, are the basis for the popular 'Paleo Diet'.2 Foragers may consume their food the same day that they gather it, while others use storage techniques for food that they hunt or gather, some of which is available only seasonally.1 Traditionally, greater than 90% of the hunter-gatherers' diet came from wild foraged foods.1,2 Today there is no living human population left on earth that obtains this much of their diet from the wild; many hunter-gatherers have access to modern convenience foods and grains from nearby towns and civilizations.1 For example, the North American Indians, or native peoples, gathered over 130 species of plants.
However, much of the information on ancient hunter-gatherers is based on observing modern-day groups that still obtain part of their food supply through foraging. Modern hunter-gatherers, such as the Hadza of Tanzania and the Philippine Tasaday, derive 50-80% of their food (by weight) from plants and 20 to 50% from animal sources.2,3 Across the globe, historically, the diet varied: hunter-gatherers living closer to the equator ate a more plant-based diet, with fewer animal sources, but those in colder climates had to rely more on meat, fish and other animal sources for sustenance.4 The Greenland Eskimos or Inuits, are hunter-gatherers living in the remote arctic whose diet is almost entirely seal and whale blubber, with very low intakes of fruits, vegetables, nuts or any food of plant origin.3,5 In the 1970's, researchers studying the Inuits speculated that this population had less coronary artery disease and other chronic health problems than other populations in the Western World. However, recent evidence shows that the cardiovascular disease was not diagnosed properly in this population due to living far from medical facilities; the Inuits have coronary artery disease, cardiovascular disease rates and other chronic disease at the same level or higher than other populations in the West.5
Hunter-gatherers both today and historically obtain food by gathering the leaves, shoots, stems and roots of plants, berries, fruits, roots, nuts, seeds and tubers (potato-like) of plants.2,3 They gathered wild eggs and honey and consumed meat, bone marrow, fish and insects from animals that they hunted.4,6 Ancient hunter-gatherers did not consume any cereal grains, dairy products, alcohol, refined oils, added salt, refined sugars or margarine.6-8 Paleolithic people, not unlike some forager populations still living in places like Australia and Africa today, consumed 40-80 g/day of dietary fiber, exponentially more than the amount consumed by the average American, 12-15 g/day.3,9 Human nutrition and health has always varied among groups, however, one thing is certain: the human diet was never this low in dietary fiber intake until the 20th century in the Western World.
So, what does this mean for public health? Why write about the diet of ancient people from eons and eons ago? For tens of thousands of years, humans ate whole, unprocessed food that they gathered. Dietary patterns are health factors we are exposed to every day and would have impacted how the human digestive tract, metabolic and endocrine system developed as well as the microbiome, or gut bacteria. Differences between the food composition in ancient forager populations compared with modern 21st century populations may explain the onset of metabolic changes leading to chronic disease. This diet, which may date back ~200,000 years in human history, is what anthropologists believe humans subsisted on for much of our existence.4
Agricultural societies did not emerge until approximately 11,000 years ago; modern industrialization and processed food is less than 200 years old.4 At the same time, humans can adapt to some extent, and we do not want to 'romanticize' the paleo diet or hunter-gatherer lifestyle as being the ideal.4 Ancient humans had a shorter life expectancy than many people in modern Western societies, and modern hunter-gatherers have a life expectancy of 35-40 years due to many dying of childhood infections.10 If they survive infectious disease a small fraction of foragers live to be in their 60's and 70's.10 The leading cause of death for Paleolithic people was infectious disease, whereas heart disease is the number one cause of death in the Western World today.10,11
In conclusion, most foragers, or hunter-gatherers had a diet composed of wild gathered and hunted food which was higher in dietary fiber than the modern diet in the Western World. Although ancient people died more from infectious diseases, they were free from many common conditions seen in the Western World today, and dietary fiber may explain this.