Average height in history and why we have grown

 The general reason for the increase of human height is improved nutrition and healthcare. Over the years, access to proper nutrition and healthcare has improved, allowing individuals to reach their full genetic potential for height. Additionally, advancements in technology and infrastructure have made it easier to transport food and medicine to various areas around the world, further improving overall health and contributing to the increase in height.

Average height has varied throughout history. 

During ancient times, such as the time of the Egyptian pharaohs and the Greek and Roman empires, average height was thought to have been around 5 feet (152 cm) for men and 4'9" (145 cm) for women. This was due to limited access to adequate nutrition and healthcare.

During the medieval times, the average height dropped to about 5'5" (165 cm) for men and 5' (152 cm) for women. This was due to factors such as frequent wars, famines, and an overall lack of access to proper nutrition.

In the 18th and 19th centuries, with the advent of the Industrial Revolution and improved living conditions, the average height started to increase. By the early 20th century, the average height for men in the United States was around 5'9" (175 cm), and for women, it was around 5'4" (162 cm).

Today, due to improved nutrition, healthcare, and living conditions, the average height for men in the United States is around 5'10" (178 cm), and for women, it is around 5'4" (163 cm). However, there are still significant variations in height between different regions and populations worldwide.