Rob Arnott of PIMCO and Research Affiliates says that he expects developed world growth to significantly lag emerging market growth in the coming years — and says investors should take heed of that when investing.

“GDP growth in the developed world faces headwinds from the costs associated with a rising debt burden, from the inevitable return to balanced budgets in the years ahead, from a shrinking workforce, and from a dearth of young adults,” Arnott writes for the Financial Times. “Meanwhile the emerging markets will enjoy a tailwind from a flood of young adults, paired with deficits and debt burdens that are, on average, light relative to the developed world.”

Arnott lays out several simple, “uncomfortable” truisms that pertain to the situation, which he says investors shouldn’t ignore. Among them:

• The rate at which a country’s workforce grows has a big effect on the rate its gross domestic product grows;

• GDP growth is produced mostly by young adults in their 20s and 30s;

• Borrowing today creates debt service costs tomorrow;

• Deficit spending, if larger than real GDP growth, cannot persist forever;

• Reducing deficit spending means reducing GDP (temporarily, until the private sector picks up the slack);

• Earnings and dividends cannot be expected to grow faster than GDP indefinitely.

Several of those facts mean U.S. GDP will be trimmed in the coming years, he says, part of what PIMCO has dubbed the “new normal” of economic growth.