Lapham’s Quarterly has put together a graphic showing how many calories a dollar will buy in various forms, including lettuce, canned tuna, a bottle of Coca-Cola and a McDouble sandwich at McDonald’s. It’s a good illustration of one of the problems with the American diet: unhealthy food is often a lot cheaper than healthy food.

One dollar’s worth of Coke has 447 calories, while $1 of iceberg lettuce has just 16.5. To look at it another way, you would have to spend about $5 to buy 2,000 calories at McDonald’s, $19 to buy 2,000 calories worth of canned tuna and $60 to buy 2,000 calories worth of lettuce.

These gaps have become larger over time, as this chart makes clear: