NYC mayor Michael Bloomberg is getting mixed reviews for his proposal to ban super-sized sugary drinks. Reader John O. wasn't impressed with this graphical effort (link):
The key problem: this picture is not scary at all. The reason it's not horrifying is that there is no context. People who have knowledge about healthy eating habits will get the message but that's preaching to the choir.
If you know that the recommended consumption of daily sugars for adults is roughly 20-36 grams, then you can see that one sugary drink of 12 ounces or higher would take you over the daily limit. A 64-ounce drink would give you more than 7 times what you need in a day. That's a powerful message but you won't know it from this chart. Not from the sugar cubes doubling as shadows, which is a cute, creative concept.
Also, make use of the chart-title real estate! Instead of "Sugar & Calories per Fountain Drink", say something memorable. "Fountain drinks make you fat and sick".
There is something else fishy about this graphic. What are the most prominent data being displayed?
You got it. They're 7, 12, 16, 32, 64. Where have we seen this type of data display?
Yup. This format is lifted from a menu in a Starbucks or a McDonald's (without prices).
Is this a health warning? Or a restaurant menu?
Also slightly confused about the slightly non-linear relationship between calories and drink size. Maybe volume of ice is held constant...
It is in fact a proportional relationship. The confusion arises from the non-linear increase in cup size from 7 to 64 ounces. The math is roughly 11 calories per ounce, and 3g of sugar per ounce. I wonder if it is better to show those two numbers instead of the ten not-very-memorable numbers shown on the chart itself.
In case you're wondering, the heights (thus areas) of the cups have no relationship with any of the data, not calories, not sugars, and not the cup size.
PS. John also wrote: "The soda cup graph reminds me of the chart from Pravda that Tufte cites in 'Cognitive Style of Powerpoint'. " If you know what he's talking about, please post a link to the chart. Thanks.