Modern economic progress began with the start of the Industrial Revolution in eighteenth-century Britain. Prior to about 1750, economic progress was so slow that people would have to be very observant to see any progress during their lifetimes. Everywhere in the world, the standard of living and the quality of life was much the same in 1750 as it was in 1650, and it was much the same in 1650 as it was in 1550. Indeed, it was much the same in 1550 as it was in 550. The remarkable transformation in the world economy that began with the Industrial Revolution is often couched in terms of growth in per capita income, and when looked at only in those terms, income growth has been remarkable. Prior to the Industrial Revolution, there was virtually no per capita income growth,1 but growth has accelerated since, so that by the beginning of the twenty-first century, growing economies could expect their per capita incomes to double every three to four decades. For most of human history, people struggled to get enough food to survive, but by the beginning of the twenty-first century, developed economies found obesity to be a greater problem than hunger. Obesity was barely possible prior to the twentieth century, except for the wealthiest individuals, and before the twentieth century obesity was a sign of prosperity. By the end of the twentieth century, poor people in the United States weighed, on average, more than the rich.2