It’s one of the more remarkable switcheroos in US economic statistics in recent years.

For the last year, retail sales at US eating and drinking establishments have outrun those of grocery stores, upending a longstanding pattern in which the bulk of American spending on food occurred at the supermarket.

Part of this reflects stagnant prices of groceries over the last year or so, with US grocery stores—Walmart is the biggest—competing with the rock bottom pricing of dollar stores. For example, over the last year, dairy and meat prices have dropped sharply.

But the other fact is that Americans have been consuming a larger and larger amount of their food away from home. It’s a well-established pattern stretching back to the 1970s that reflects the surge of female participation in the labor force outside domestic labor.

Is the trend toward eating out a problem? Well, it hasn’t been great for American health. As the amount of calories Americans consume away from home has increased—from 18% in 1978 to 32% in 2008—it should be noted that food consumed away from home is markedly higher in salt, saturated fat and sodium while lower in dietary fiber. Other studies cite the rising American propensity for dining out as a potential contributor to the rise in US obesity.