With China set to overtake Japan as the world’s second largest economy in 2010, the Chinese consumer could also dethrone Japan in another key category in the next few years, according to a new report by Credit Suisse.

In its first Global Wealth Report, Credit Suisse predicts that total household wealth in China could more than double to $35 trillion by 2015 from $16.5 trillion at the moment. China currently is third in terms of the total share of global wealth after the U.S. and Japan, at $54.6 trillion and $21 trillion respectively, and is 35% ahead of France, the wealthiest European country.

A decade ago, China stood at seventh place in the global share of wealth. In the same period, Japan’s wealth only rose by 5%, largely because its adult population growth grew at a negligible 3% while equities and house prices have stagnated.

China has the largest proportion of what Credit Suisse calls the ‘middle segment’, or individuals with $10,000 to $100,000, or 60% of the global total of 1.05 billion people. This group comprises 23.5% of the global population and holds 16.5% of total wealth.

Giles Keating, global head of research for Credit Suisse’s private bank, said that it is this group which will be key in “reshaping the global economy” in the future, particularly as wealthier consumers in emerging markets shift from food to discretionary items.

For example, while food made up 34% of Chinese consumption in 2005, that number is expected to fall to 25% in 2015. Naturally, spending on health care, recreation and transportation is only going to increase.

“China’s investment rate as a percentage of gross domestic product is still at around 40%, which allows for very rapid capital accumulation,” said Keating at a media briefing in Hong Kong.

In contrast, the top 10 countries by level of total household debt are all developed Western economies, with the exception of Japan which is second after the U.S. South Korea has the largest total household debt out of Asian emerging markets at $830 billion, which is 6% of the U.S. level of $13.97 trillion.

– Isabella Steger