I put this together on Tuesday, with data from the Bureau of Labor Statistics. It shows the price of different foods and beverages over the last three decades. The price of each food or beverage is set equal to 1 in January 1978, and the chart then shows how the price has changed since then.

It’s a fairly striking pattern. Unhealthful foods, with the exceptions of cookies (the blue line), have gotten a lot cheaper. Relative to the price of everything else in the economy, sodas (the orange line) are 33 percent cheaper than they were in 1978. Butter (dark brown) is 29 percent cheaper. Beer (gray) is 15 percent cheaper.

Fish (the yellow line), by contrast, is 2 percent more expensive. Vegetables (purple) are 41 percent more expensive. Fruits (green) are 46 percent more expensive.

The price of oranges, to take one extreme example (not shown in the chart), has more than doubled, relative to everything else. So if in 1978, a bag of oranges cost the same as one big bottle of soda, today that bag costs the same as three big bottles of soda.

In my column this morning, I mention that the average 18-year-old today is 15 pounds heavier than the average 18 year-old in the late 1970s. Adults have put on even more weight during that period. The average woman in her 60s is 20 pounds heavier than the average 60-something woman in the late 1970s. The average man in his 60s is 25 pounds heavier. When you look at the chart, you start to understand why.