Scientists estimate that the earliest hominins arose around 6 million years ago, and it took that much of a time for human evolution to achieve the stage of modern humans. During most of this span of time, humans walked barefoot, so our foot structure and walking style have adjusted for walking in such way. Specifically, our soles have developed a rich and extensive neural network that can detect discomfort in our feet when walking. As a result, we naturally and continuously adjust our posture while walking in order to avoid damage to the joints. However, wearing shoes impairs such ability.

With a history of barely more than 45,000 years, wearing shoes is a new fashion that only appeared relatively recently compared to the 6 million years of human evolution. Hence, as far as our bodies are concerned, wearing shoes is still a new territory. Our feet have yet to totally adapt to this new environment, which has led to a series of problems. Studies have shown that foot diseases such as flat foot and Beriberi can be easily induced by placing feet in humid, deoxygenated, and closed conditions over an extended period, such as in a shoe.

As a matter of fact, in the wake of changes in our living conditions, more and more diseases have emerged due to our body's inability to adapt to the new environment. These diseases are also known as 'mismatch diseases.' For example, high blood pressure, diabetes, coronary heart disease, cancer, depression, and anxiety.

Seeking to understand the causes, preventions, and cures of mismatch diseases, this popular science book begins with a modern context and then looks back on the history of human evolution. In this book, you will get to know the evolutionary origins of all our body parts, and why they developed as they did, and in what environment they are formed.