The Stone Age diet is based on the theory that modern human genes result from the way of life people lived for over a million years before the introduction of agriculture.
Consuming the diet of those times, they say, is good for humans.
Other names are the Paleolithic, or paleo diet, the prehistoric diet, the caveman diet, or the hunter-gatherer diet.
Unlike the raw food diet, food on the Paleo diet can be cooked.
People seeking to lose weight may find they achieve this goal without having to count calories, at least at the beginning. This is because they will probably consume fewer calories than they were before, just by avoiding processed and refined foods.
Farming began about 10,000 years ago, but humans have been around for over a million years. The Paleolithic era ended about 20,000 years ago, before the introduction of agriculture.
This suggests that, genetically, we are nearly identical to humans who lived before the start of agriculture.
Paleo dieters maintain that 10,000 years is not long enough for natural selection to make the genetic changes needed for us to consume our relatively new farm-based diet.
Farming produces grains, legumes, and dairy product, but our genetic makeup is still that of the hunter-gatherer. In other words, our bodies are designed to consume wild plants, animals, and seafood.
We are even less genetically suited for modern processed foods, such as sugar, refined fat, and so on.
The paleo diet is not intended as a high-protein diet. However, the foods included in the diet are higher in protein, fiber, and fat than the average western diet, and lower in sugar, salt, and starchy carbohydrates.
Hunter-gatherer foods that are suitable for the paleo diet include:
- Insects and larvae
- Seafood, both fish and shellfish
- Vegetables, including those root vegetables that can be eaten raw
- Fruits, nuts, and seeds
- Herbs and spices
- Natural sugars, such as honey, maple sugar, and date sugar
According to paleo dieters, humans are not designed to eat:
- Grains and flour
- Legumes, including peanuts, beans, peas, cashews, tofu, soy milk, and soy flour
- Root vegetables that cannot be eaten raw, such as potato, tapioca, parsnips, sweet potato, and yam
- Refined sugars
- Foods that contain yeast
- Juices, sodas, and coffee
- Dairy products
- Processed meats
Since the paleo diet was introduced, new versions have emerged that allow some "modern" foods that scientists have proven to be healthy, such as quality bacon from pasture-raised pigs.
Some suggestions for meals are:
- Breakfast: bacon, eggs, and a piece of fruit
- Lunch: a sandwich of meat and vegetables wrapped in a lettuce leaf
- Dinner: fried chicken with vegetables
- Snacks: raw vegetable sticks, nuts, or fruit
Authority Nutrition suggests that a little good quality red wine and an occasional piece of dark chocolate are "sensible indulgences."
Some research has suggested that the paleo diet can reduce weight and improve cardiovascular health.
Research suggests that weight loss may occur. In one study, participants lost
Others, however, suggest that the lack of nutrients from whole grains, for example, may lead to deficiencies.
Researchers in Sweden compared the effects of the paleo diet with the effects of a diabetes diet in 13 patients. All the participants had had diabetes type 2 for an average of 9 years. They followed one diet for 3 months, then the other for 3 months.
The researchers found that glycemic control and several cardiovascular risk factors were better following the paleo diet, compared with the diabetes diet.
Comparison with Mediterranean diet
The participants were randomly selected to follow one of the diets for 12 weeks.
The authors reported that the Paleo diet had better results than the Mediterranean diet in improving glucose tolerance and achieving a lower dietary energy intake.
The participants were more likely to report feeling full with the Paleo diet than with the Mediterranean diet.
Reviewing the Swedish studies and other research, Dr. David Klonoff concluded in 2009 that "The Paleolithic diet might be the best antidote to the unhealthy Western diet."
However, according to the British Heart Foundation, avoiding dairy products and starchy foods, such as whole grains, can mean a lower intake of calcium, fiber, and energy, and this could have a long-term impact on health.
Some experts argue that we are not like our stone-age ancestors. We live a different kind of life than they did, and the species they consumed at that time have changed. Many are no longer available in the form they took then.
People of the Stone Age were also far less sedentary than most people today, as they had to hunt their own food and did not have the same means of transportation as we do.
Moreover, even 10,000 years ago, diet varied according to where people lived and what was available.
The Kung tribes of southern Africa, for example, appear to have consumed milk and cornmeal and very little meat and fish, while the diet of the Inuit of North America consisted mostly of fish and meat, with a little fruit and vegetable.
Critics also point out that our genes have changed. Many humans have adapted to consume lactose, and the gut microbiota changes relatively quickly. People have also adapted to consume legumes and grains.
It is not known exactly what people ate at that time in which proportions, or if they were any healthier than we are now.
While the paleo diet has been shown to aid in weight loss and to decrease the progression of cardiovascular disease and diabetes, the research remains inconclusive. Study populations have been small, and the time periods were short, from 10 days to 12 weeks. Some did not involve a control group.
The paleo diet, or a modified version, may be a good way to eat less processed and refined foods and to increase the intake of vegetables and fruits. This can lead to overall improvements in health.
However, it is always important to find a balanced, nutrient-dense diet that works with and agrees with the individual's particular body and lifestyle.