We wrote a while back about the problem of “calorie density“—namely, that junk foods filled with fats and sugars are way, way cheaper than healthier foods such as fresh fruits and vegetables. And, depressingly enough, the price gap between healthy and unhealthy foods widened in the 1980’s and 1990s.

So even though it’s technically true that food in America is cheap, healthy food is effectively out of financial reach of many low-income folks. (In some cases, healthy food is physically out of reach too.)

Well, apparently the problem is getting even worse.

The first-of-its-kind study by UW researchers found that between 2004 and 2006, the costs of some healthy foods went up nearly 20 percent at major Seattle supermarkets. But over the same period, the cost of some junk foods dropped.

“Healthy foods are gradually slipping out of reach for all but the affluent consumers,” said Adam Drewnowski, director of the University of Washington Center for Public Health and Nutrition and an author of the study.

Jeez, what’s it going to take to bring some justice—or just plain old sanity—to the food system?