“Life can only be understood backwards; but it must be lived forwards.” Søren Kierkegaard
Since the 1970s, the Paleo diet has been in and out of fashion. The idea that humans evolved eating specific foods that keep them healthy was first inspired by a man named Joseph Knowles. In the early 1900s, Knowles spent two months in the woods of Maine to live like our ancestors of the Stone Age and became famous for his survival.
He reported in detail how he ate fruit and vegetables before he learned to fish and hunt. Although he lost more than ten pounds, his muscles got bigger and his lung capacity improved. Knowles’ experiment suggested that hunting and gathering food makes people stronger and healthier.
It wasn’t until the 1970s however that the Paleo diet was first popularised. A gastroenterologist Walter Voegtlin wrote a book The Stone Age Diet: Based on In-depth Studies of Human Ecology and the Diet of Man, where he described how the paleo diet could improve our health and well-being.
So, what exactly is the Paleo diet?
The concept of the Paleo diet is based on the principle that we mimic the foods of our human ancestors from the Paleolithic period - the time from the early use of stone tools, about 2.6 million years ago up to the start of civilisation that is about 10,000 years ago. The advocates claim that since we began eating a different kind of foods after the advent of agriculture we become less healthy and more prone to diseases.
The Paleo diet recommends unprocessed foods including meat, fish, selfish, eggs, vegetables, fruit nuts and seeds. We should eliminate sugar, dairy and grains although some dairy products and rice are often allowed.
Does the Paleo diet improve our health? Let’s go to the research.
A study published a few years ago was looking at how the Paleo diet may influence glucose tolerance in people with coronary heart disease in comparison to the Mediterranean diet. The researchers enrolled 29 men with heart disease and high blood sugar levels or type 2 diabetes, to either the Paleo diet or the Mediterranean diet with no calorie restrictions.
After twelve weeks, the researchers measured glucose tolerance, insulin levels, weight and waist circumference. It turned out that only the Paleo diet group saw a significant improvement in glucose tolerance. All men in the Paleo group ended up having normal blood sugar levels and a significant reduction in waist circumference, compared to those on the Mediterranean diet.
Although both groups lost weight; 5kg (11lbs) in the Paleo group and nearly 4kg (8lbs) in the Mediterranean group, the difference wasn’t significant. Scientists concluded that the Paleo diet led to greater improvements in waist circumference and glycemic control, compared to the Mediterranean diet.
In a small observational study published in the European Journal of Clinical Nutrition researchers enrolled 14 healthy medical students to see how the Paleo diet may affect body weight, waist circumference and blood pressure. All participants eat the Paleo diet for three weeks. The researchers reported that most participants lost weight. Their body mass index decreased on average by 0.8, their waist circumference went down by 1.5cm, and there was a mild reduction in systolic blood pressure.
A randomised cross-over study published a few years ago in Cardiovascular Diabetology was looking at how the Paleo diet may affect cardiovascular risk factors in people with type 2 diabetes. Researchers asked 13 people with type 2 diabetes to eat either the Paleo diet or a typical diabetes diet. All participants were on each diet for three months at a time. It turned out that people on the Paleo diet lost more weight and had more waistline reduction, compared to the diabetes diet.
The Paleo diet group also had lower levels of HbA1c, a diabetes marker, higher levels of HDL, the good cholesterol, and lower levels of triglycerides compared to the diabetes diet group. Scientists concluded that the Paleo diet caused several improvements in cardiovascular risk factors and more weight loss than the diabetes diet.
These findings were confirmed in another observational study where researchers were looking at how the Paleo diet may be associated with insulin sensitivity, liver fat and muscle cell fat. The scientists asked ten healthy women with body mass index over 27 to eat the Paleo diet for five weeks. Scientists observed major reductions in liver fat, weight loss and significant improvements in several import risk factors like fasting blood sugar levels, total cholesterol levels and blood pressure.
Although the vast majority of available studies have serious limitations, like poor design, a small number of people, short duration or lack of control arms, they show an association between the Paleo diet and some health benefits.
The Paleo diet is a modern fantasy concept that encourages us to eat like lithe cavemen. Although there’s nothing wrong with this fantasy, we need to acknowledge that it’s just imaginary world. There is no real way to recreate the Palaeolithic diet in the 21st century. We don’t even know what these people really ate; there was not one diet that all Palaeolithic people followed, simply because their primary goal was to survive.
We live in a very different reality. Our bodies have been conditioned by thousands of years of civilisation. Scientists have long recognised that we have developed new adaptations like the ability to better digest starch or tolerate dairy products. Our patterns of movement, living habits and daily challenges remotely resemble those of cavemen.
Most of the Palaeolithic foods are no longer available to us. The foods in our stores have been selectively bred for centuries to create the most useful products we now consume.
We can’t adopt an ideal diet out of the distant past because we don’t live in the distant past. What we can do, however, is to learn from those hunter-gatherers, get inspired and adopt what works best for us.