The Paleo diet is a style of eating based on hunter-gatherer principles from the Paleolithic era, between 2.5 million and 10,000 years ago. The main purpose of the diet is to eliminate processed foods that have been linked to a litany of health problems. The diet is focused on consumption of lean meats, fruits, vegetables, nuts, seeds and fish. A good rule of thumb when practicing the Paleo diet is if a particular food is available as a result of organized agriculture then it cannot be eaten.
Dairy, legumes and most grains are not allowed on a strict Paleo diet as they are the result of agriculture, however, they are good sources of calcium in the case of dairy and fiber in the case of grains and legumes and are generally an integral part of a well-balanced diet. Alcohol, coffee and tea are also not allowed in the Paleo diet.
The Paleo diet can be a good tool for weight loss as it eliminates all processed foods and focuses on sources of lean proteins and an abundance of fruits and vegetables. Large amounts of seeds, nuts and leafy greens should be consumed when on the Paleo diet to ensure enough dietary fiber, as grains tend to be one of the main sources of fiber in the typical American diet.
Proponents of the Paleo diet assert that it is necessary to return to our ancient eating habits, as our bodies have not evolved to be able to properly metabolize much of what is in the modern diet. One argument against this assertion is that the diets of ancient humans varied widely depending on geography; the diets of ancient humans in northern Africa versus the diets of those in northern Canada relied on completely different food sources. One thing that all medical experts agree on is the limiting of processed foods, for this reason alone incorporating some aspects of the Paleo diet is beneficial.
The Paleo diet can be very difficult to adhere to because of how restrictive it is. Since the diet consists primarily of meat and fresh fruits and vegetables it can also be expensive, even more so if the diet is strictly followed by consuming only organic produce and grass fed meat. Due to these challenges and the possibility of nutrient deficits because of eliminating entire food groups, most people who practice the Paleo diet tend to modify it in order to make it easier to stick with.