Wednesday, June 13, 2012

Body Weight in the United States - Part 2, "Non Factors"

yearly alcohol consumption graph united states

Sometimes the story isn't what is a trend, but rather what is not a trend. In this second installment about body weight in the U.S., listing what doesn't seem to be contributing factors will help narrow down what might actually be the problem(s).

Alcohol

"Stay busy, get plenty of exercise and don't drink too much. Then again, don't drink too little."
     - Herman "Jackrabbit" Smith-Johannsen

Sage advice from a person who lived to be 111 years old.



Alcohol has been around since 10,000 B.C., starting with beer. In fact, it may have preceded bread which, as will be discussed in the next article, might be a contributing factor to weight gain. Perhaps the ancients had it right by 'drinking' their bread...

Looking at the above graph, alcohol consumption hasn't changed all that much since 1960. Peering back even further, Americans are remarkably consistent when it comes to having that 'wee nip' at the local pub. Considering the explosion in the variety of drinks available today, humans are adept at moderating their intake of spirits.

Therefore, one cannot say that alcohol consumption is related to weight gain as a trend in this country.

Exercise (during leisure time)

Surprise! American are not sitting around as much as they used to during their leisure time (time not working or commuting to work). That means that when not working, we are more active now than in the past as the graph below shows:

annual sedentary trend chart

With over 50 million health club memberships and nearly 30,000 health clubs, it appears that Americans are collectively pumping more iron then ever before. Go to any spa after work and it will be filled to capacity with people on every imaginable machine. Being an avid cyclist, this author has personally witnessed a cycling boom all over the country.

Just try going to a garage sale and not seeing some sort of exercise equipment for sale. Yes, that means that it's no longer being used in that household, but once sold would be used in a new household (hopefully).

There isn't an (obvious) relationship between leisure-time exercise and weight gain. Of course, exercise can come at other times and this will be examined in the next article.

Does that mean that all that effort is wasted? No, not at all. People are getting heavier in this country and it seems likely the rate at which that occurs would increase if people stopped working out altogether.

Nutrients (micro)

Micro-nutrients (vitamins and minerals) are those that are needed in small quantities while macro-nutrients (carbohydrates, fats, protein, water, etc.) are those needed in large quantities. Click here to see a detailed description. Insufficient quantities of micro-nutrients can lead to several diseases, most of which have been eliminated in the U.S. due to our ready supply of fortified food.

Even so, is it possible Americans, on average, are not getting enough micro-nutrients? In other words, could this partially explain the rise in body weight over the last fifty years?

yearly u.s. micro nutrient levels


Looking at the graph above, it is important to see that consumption of micro-nutrients has remained fairly steady for over a hundred years. The chart isn't designed for individual nutrient clarity, but rather to paint a broad stroke so that the reader can see most of the lines are fairly level. Sodium and potassium levels are marked, however, since those two nutrients are frequently mentioned. Over time, sodium intake has gone up while potassium intake has gone down - not by a large amount, but it's worth noting.

That being said, excessive sodium intake will lead to water retention which has a weight of approximately 8.3 lbs per gallon (1kg per liter). So, while sodium does not contribute to fat gain, it does lead to body weight gain holding on to all that water internally.

Even including sodium, the micro-nutrients in our food have remained rather stable. Therefore, it is reasonable to assume weight gain in the U.S. isn't attributable to this particular aspect of our food.

Conclusion

Alcohol, leisure-time activity and micro-nutrients - when taken as a whole - do not appear to be factors for U.S. citizens gaining weight. More than likely there are individual cases where this isn't true, but this article refers to overall trends. It should be noted that this article isn't cause to drink more, exercise less or eat junk food - doing one or more of those activities will probably make you fatter. What is being said is that Americans don't drink enough for it to be a factor, nor do they exercise too little in their leisure-time (as opposed to other times), nor has our food become less nutritious (at the micro level) - on average.

So why are we getting fatter if the above hold true? Come back next week for Part 3 of this series to find out.



Questions:
1) Will somebody ever make alcoholic drinks packed with vitamins and minerals?
2) Is there a link between malnutrition and democracy index?
3) What other surprising phenomena aren't related to weight gain?

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(subset(alcohol.frame, Country=="United States"), aes(x=Year, y=Value, group=Year)) +
    geom_point(color="blue", size=2.5) +
    geom_line(aes(group=1), color="blue", size=1.1) +

    
    ylab("Amount (Liters per Capita)") +
    xlab("Year") +
    
    scale_y_continuous(limits = c(5,15)) +
    
    opts(title="Annual (per capita) United States Alcohol Consumption",
        legend.title = theme_blank(),
        panel.background = theme_blank())

2nd graph:
ggplot(sedentary.frame, aes(x=Year,y=Percent.Sedentary.During.Leisure)) +
    geom_point(size=2.5, color="blue") +
    geom_line(size=1.1, color="blue") +
    
    ylab("% Sedentary") +
    xlab("Year") +

    scale_y_continuous(limits = c(0,100)) +
    
    opts(title="% Sedentary During Leisure Time",
        legend.title = theme_blank(),
        panel.background = theme_blank(),
        axis.line = theme_segment(),
        plot.margin = unit(c(0, 3.5, 0, 0), "cm"))


Further Reading:

2 comments:

  1. What we don't know is if the people exercising are the ones getting fatter. If you split the exercise line by overweight and not overweight, would they be equal? It could be that the skinny are exercising more (and staying skinny) and the heavy are exercising less and getting heavier.

    Your approach is very interesting and while I don't think it can very well stand on its own statistically, it is nevertheless a great start.

    ReplyDelete
    Replies
    1. Tom -

      Agreed. Unfortunately, the data came from different sources so the same people weren't being tested in each scenario. That being said, I do think that the trends are informative and hold value. Next week's article will help focus the picture a bit more.

      Perhaps somebody will take the ball and run further down field with it from here.

      Delete

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