U.S. manufacturing jobs have long been moving overseas, leaving large parts of the country with empty factories. It’s happened so much, the term “Rust Belt” was created to describe the landscape of cities such as Detroit which have been in economic decline for decades.

Little noticed, the United States has also been exporting a taste for fast food.

Hamburger giant McDonald’s enjoys annual sales of more than $120 billion at its franchises around the world, and the United States represents about a third of its sales. Europe contributes more to the company’s revenue than the 13,000 Golden Arches in the United States.

The most recent quarterly earning report shows that sales growth of 5 percent was outpaced by an 8.1 percent increase in stores open in Asia, the Middle East, and Africa.

Burger King, Wendy’s, and other fast-food chains report the same trend.

Sales and profits are growing faster in overseas markets than they are in the United States.

Yum Brands, parent of fast-food staples KFC, Taco Bell, and Pizza Hut, is focused on Asia for the future. There are more than 3000 KFC outlets in China, and more than 700 Pizza Huts.

Yum management emphasized their leadership position in Vietnam and Malaysia at a recent presentation for Wall Street analysts.

Vietnam and Malaysia are frequently mentioned as fast-growing economies.

Their growing middle classes are showing an appetite for American foods. It may not be healthy, but it may be a profitable trend for investors.