The most effective diet is the one to which we are genetically adapted. If we take a moment to consider our genetic evolution, it is clear that changes to the human diet have occurred far too quickly for the human genome to adapt. We are genetically identical to our ancestors of 20,000+ years ago. Our physiology is adapted to living as hunter gatherers for the 2 million years leading up to the agricultural revolution (the Palaeolithic era).
The first evidence of any sort of domestication of plants or animals comes from around 10,000 years ago. Although this sounds like a long time ago, human history dates back 2.5 million years! We have therefore been living as hunter gatherers for over 99.5% of our evolutionary history! When you then consider the even more dramatic changes to our diets that have occurred in the last 200 years since the industrial revolution, it becomes clear that our genetic code is not suited to the way we now eat.
Anthropology research has shown us that our hunter gatherer ancestors were taller than we are and virtually free of tooth cavities and bone malformations. Additionally, despite their lack of medical care, they experienced an extremely low rate of infant mortality. Ancient tribes that continue to this day to eat a hunter gatherer-style diet do not suffer from chronic diseases such as diabetes, cancer and heart disease.
Modern advances in medical care have given us the ability to treat trauma and infectious diseases, which has improved our life expectancy; however the interaction of our hunter gatherer genetic code with our modern lifestyle has led to an epidemic of chronic disease and obesity. This can be largely attributed to the dramatic change in our diets over the last 200 years or so.
Before the development of agriculture, human diets would have been limited to unprocessed wild animal and plant foods. Today cereal, refined sugars, refined vegetable oils, dairy products and alcohol make up over 70% of our diets! The biggest contributor to obesity and chronic disease is arguably the increased consumption of sugar. Research suggests that our hunter gatherer ancestors ate the equivalent of about 22 teaspoons of sugar per year. Today the average person consumes 70kg of sugar per year! These refined sugars are devoid of any vitamins or minerals, leaving us deficient in many.
Now onto the easy part: what constitutes a healthy diet? Quite simply, a healthy diet should be composed of high quality proteins and fats (coming from meat, fish, eggs, nuts, seeds, avocados, olive oil etc.) and lots of fruit and vegetables (they should make up the vast majority of your carbohydrate consumption). Try to avoid grains (yes, even whole grains!), processed food and sugars, alcohol, and if trying to lose body fat, starches as well. At first glance this may seem difficult; however there are thousands of great “Paleo” recipe books and websites to help get you going. These are very straightforward guidelines and they will improve your health and body composition far more effectively and sustainably than any calorie restricted diet you may have followed.