American Society For Nutrition

Practical Applications of Nutritional Science: Matt's Law of Pizza Allocation

Practical Applications of Nutritional Science: Matt's Law of Pizza Allocation

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Posted on 04/12/2010 at 09:43:09 AM by Student Blogger
By: Matt T.

So my wife and I had a common dispute over the weekend. Given 8 slices of pizza and multiple hungry parties, who gets what share? Back in the years BT (Before Taylor, our three-year old boy) the pizza was split in half. It just seemed fair. However now we have a little house elf who makes off with a slice before we can stop him, and are left with 7 slices to divide. What to do?

After some deliberation, I decided the most truly fair way to distribute food is according to need. (Actually I have maintained this for some time, but the logic of dividing an even number of slices 2 ways has been formidable)...

Falling back on my nutritional science training, I whipped out the trusty Harris-Benedict Equation.

For the non-nutritionists among you, the Harris-Benedict is a system for estimating daily calorie requirement based on age, body size, gender and a rough approximation of calories burned in physical activity. It works like this:
The Basal Metabolic Rate (BMR), or Calories burned in 24 hours of laying in bed, is calculated first. Similar equations with a few differences are used for men and women.

For men, BMR = 66+ (6.23 * weight in pounds) + (12.7 * height in inches) - (6.8 * age in years).

For women, BMR = 655 + (4.35 * weight in pounds) + (4.7 * height in inches) - (4.7 * age in years).

Go ahead an calculate your BMR; it's a chance to answer that question we asked back in high school algebra: "When are we ever going to use this?" Keep in mind these yield rough approximations that do not account for individual differences in metabolism, etc. It's a common rule of thumb to allow "plus or minus 10%" of the estimate to account for this uncertainty.

You obtain the Harris-Benedict estimate of total Calories burned in a day by multiplying the BMR by 1.2 if you are, generally speaking, sedentary, by 1.375 if you are lightly active (say, working up a light sweat around 3 days of the week), by 1.55 if you are moderately active (engage in regular exercise that gets the heart pumping at a brisk pace), by 1.725 if you exercise hard basically every day and by 1.9 if you are an athlete in training. (Again, these are only approximations, but you get the idea. Remember Michael Phelps' diet?) Depending on your individual metabolism, this estimate is about what you would need to consume in order to maintain your current weight. To lose weight, Registered Dietitians typically make an initial Calorie prescription for weight loss by subtracting no more than 500 Calories from this estimate.

So, granting Taylor his 1 slice of the pizza pie (because that's all he'll eat, though he usually tries to get it in the form of one bite out of each slice in the box...), and dividing the rest of the pizza according to each adult's estimated caloric requirement, this is what we come to:

Matt1.JPG

Note that, to remain above the obvious criticisms, I use a higher physical activity factor for April than for myself, because she is more religious about using the exercise bike than I, and because she's usually the one chasing down our rogue house elf. Also, going strictly by the numbers, April is entitled to 1/10th of my 4th slice; however, this 10th is well within our 10% margin or error, and therefore not statistically significant.

The logic of placing the calories where they are needed is indisputable, and so I give you Matt's Law of Pizza Allocation:
An individual's fair share of pizza (as a percent of total pizza available) = 100 * (the Harris-Benedict estimate for the individual in question) / (the sum of Harris-Benedict estimates for all invested parties.) As a matter of pragmatism, I recommend rounding shares to the nearest whole slice.

The numbers speak for themselves. Regarding all who dissent from this Law of Nutritional Science I say, let them eat cake (...instead of pizza pie).

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