Thursday, July 29, 2010

Media Math

Two engineering degrees hang from the wall in my home office. I only share this fact because it explains why I wrote this post. I'm a nerd.

My pal @Baconator linked to an NPR article about the health impact of eating meat. I started reading and got stuck on this paragraph:
"In fact, people gained about 4 more pounds over a five-year period for every extra 250 grams of meat they ate daily, according to a new analysis of a large European nutrition study. That's like adding a 450 calorie steak to your dinner every night"
Whatever does it mean? Is this data surprising at all? In which direction is it surprising, too much fat gain, or too little? I dug in my desk drawers for my engineering cap.

Basic principals
  • From the NIH, 1 ounce prime steak has 75 calories, or 2.65 calories per gram.
  • From the Mayo clinic, there are 3500 calories per pound of fat.
  • There are 365 days per year, rounding down.
My initial thoughts are that nutrition discussions have units issues. Pounds? Calories? Grams? I count at least two different measurement systems. Isn't that how we crashed those NASA probes into Mars?

And the calorie by itself has problems, just read about it in Wikipedia. Won't someone think of the poor children who have to learn this stuff?


Let's get back to the article. It sounds like they are saying that:

250 grams meat * 5 years = 450 steak calories * 5 years

That means that:

250 grams meat = 450 steak calories

What if the meat is chicken?

250 grams chicken = 450 steak calories

How about pork?

250 grams pork = 450 steak calories

Ok, that seems odd. And wrong. Lets assume they meant that:

250 grams steak = 450 calories


250 grams steak = 450 calories = 2.65 calories per gram steak * 250 grams steak = 662.5 calories

Huh? For every 1.5 steak calories, it seems that only 1 sticks to your belly over a five year period. There is a 33% off sale on steak calories! The paragraph seems to be saying that over five years, eating more steak is a deal. I wonder how fruits and veggies stack up against steak.

More Analysis

Ok, let's look at it from the fat gain perspective. Four pounds in five years.

calories in 4 pounds fat = 3500 calories per pound * 4 pounds = 14,000 calories

Ok, let's assume the best case, that this is like eating 450 calories of steak per night.

14,000 calories over 5 years = 450 calories * 365 * 5 = 821,250 calories

What? From this perspective, steak seems like an even bigger deal! Eating an extra eight hundred twenty one thousand and two hundred fifty calories results in only fourteen thousand calories of additional belly fat. Only 1.7% of the calories stuck!


So, what does this all mean? What does it prove? First, it proves that math makes no sense. Second, it indicates that I probably do not understand what the article is trying to say.

If you understand what is going on, please let me know in the comments!

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