Body Weight in the United States – Part 1, "The Problem"

June 6, 2012
By

(This article was first published on Graph of the Week, and kindly contributed to R-bloggers)

annual bmi chart

The Problem

In the United States, people are getting fatter and they are doing so at an alarming rate.

So What?

Being fat isn't just a social stigma - it's unhealthy in nearly every facet of life. Staying in this condition brings high blood pressure, diabetes, asthma and arthritis to name but a few. Additionally, an obese person has a much harder time 'doing stuff' in terms of physical activity.

Want to know what it feels like? Strap on a fifty pound backpack and go for a walk. Better yet, try running with that extra weight and you will see just how much it impacts your ability to exercise let alone your ability to enjoy it. Do this daily for years and your joints will be set up perfectly for a lifetime of pain and stiffness.

Kudos to our military personnel (and any other job where this is required) who wear at least that much gear every day while performing their duties.

For the rest of us, an honest assessment is needed to reverse this trend.

BMI

Do you know your BMI (Body Mass Index)? Click here to access the National Heart, Lung and Blood Institute's calculator.

Once you have your BMI, look at the above chart. Where do you stand? If you are muscular, the calculator tends to overestimate while if you are older it may underestimate. That being said, it will still be in the ballpark because humans all share the same basic anatomy.

 Heavier People

Ignoring BMI and only looking at body weight, it is obvious that people are heavier. Adult men on average have gained about 25 lbs (11.3 kg) from 1960 through 2002:

average body weight chart
Average weight for adult men.

That's about 0.6 lbs (0.27 kg) per year. Like many trends, it doesn't seem so bad when describing the rate, but over time it adds up rather quickly.

Taller People

Since 1960, people have grown taller - about 0.9 inches (2.29 cm) taller for women and about 1.1 inches (2.79 cm) taller for men. So we are taller and heavier. That would explain some weight gain, but does it account for all 25 lbs? A little bit of math will reveal the answer:


1960:                    166.3 lbs / 68.3 inches    2.43 lbs/inch

2002:                    191.0 lbs / 69.4 inches    2.75 lbs/inch

The above calculations show that we are heavier per inch of height - about 1/3 lb more. Therefore the extra height does not explain all of the extra weight gain.

How much should an average height male weigh today?

If we were to measure how much we would weigh in 1960 given our extra height, it would come out to about 169 lbs! Compare that to 191 lbs - a difference of 22 lbs (10 Kg)!

Conclusion

People in the United States are getting taller and heavier. The rate of the former (height) is much slower than the latter (weight). People are becoming more unhealthy as a result. Additionally, it can be difficult to enjoy life when toting around those extra pounds. The only resolution to this problem is to lose weight - permanently. The next two articles will present information why this trend has occurred while also shedding light on ways to possibly reverse it.



Questions:
1) How long can this trend continue?
2) What is the burden on health care due to obesity?
3) Are other countries experiencing similar problems?

Data:
Code:
These graphs were generated using the 'ggplot2' and 'maps' packages within the R programming language. Additional graphics were created/edited using GIMP.

1st graph:
ggplot() +
    geom_line(data = subset(bmi.frame, Description == "Obese (BMI >= 30.0)"), aes(x=Year, y=Median, color="Obese (BMI >= 30.0)"), size=2) +
    geom_line(data = subset(bmi.frame, Description == "Overweight (BMI >= 25.0 and BMI <= 29.9)"), aes(x=Year, y=Median, color="Overweight (BMI >= 25.0 and BMI <= 29.9)"), size=1) +
    geom_line(data = subset(bmi.frame, Description == "Neither overweight nor obese (BMI <= 24.9)"), aes(x=Year, y=Median, color="Neither overweight nor obese (BMI <= 24.9)"), size=1) +
    
    geom_point(data = subset(bmi.frame, Description == "Obese (BMI >= 30.0)"), aes(x=Year, y=Median, color="Obese (BMI >= 30.0)"), size=3) +
    geom_point(data = subset(bmi.frame, Description == "Overweight (BMI >= 25.0 and BMI <= 29.9)"), aes(x=Year, y=Median, color="Overweight (BMI >= 25.0 and BMI <= 29.9)"), size=2) +
    geom_point(data = subset(bmi.frame, Description == "Neither overweight nor obese (BMI <= 24.9)"), aes(x=Year, y=Median, color="Neither overweight nor obese (BMI <= 24.9)"), size=2) +
        
    ylab("% of Population") +
    xlab("Year") +
    
    scale_colour_manual(values=cbPaletteNoGray) +
    
    opts(title="Body Mass Index (BMI) in the United States",
        legend.title = theme_blank(),
        panel.background = theme_blank(),
        axis.line = theme_segment())

2nd graph:
ggplot(weight.frame, aes(x=Date.Range, y=Weight.lb)) +
    geom_point(aes(size=Weight.lb), color="dark red") +
    geom_line(aes(group=1, size=Weight.lb), color="dark red") +
    geom_smooth(aes(group=1), size=1, color="black", method="lm", na.rm=FALSE, fill=NA, linetype=2) +
    
    
    ylab("Weight (pounds)") +
    xlab("Year Range") +
    
    opts(title="Weight Gain in the United States",
        legend.title = theme_blank(),
        panel.background = theme_blank(),
        axis.line = theme_segment())


Further Reading:

To leave a comment for the author, please follow the link and comment on his blog: Graph of the Week.

R-bloggers.com offers daily e-mail updates about R news and tutorials on topics such as: visualization (ggplot2, Boxplots, maps, animation), programming (RStudio, Sweave, LaTeX, SQL, Eclipse, git, hadoop, Web Scraping) statistics (regression, PCA, time series, trading) and more...



If you got this far, why not subscribe for updates from the site? Choose your flavor: e-mail, twitter, RSS, or facebook...

Comments are closed.