J Leonard Dixon

In the previous chapter I documented changes that occurred in food intake in the period after 1970. If that was all that occurred, it is possible that the energy regulation system in most individuals could have withstood the powerful forces that they faced concerning super palatable foods.

But in addition to the major changes that occurred in the availability of kcal in myriad foods and the explosion in fast food restaurants, another major earth quake was taking place in American society.

At the exact same time that there were major changes in food supply and consumption, there occurred many changes in the ways Americans accessed media – all due to the advances in transistor based technologies.

The graph below shows the history of TV over its first 75 years. By about 1960, over 90% of households contained a black and white TV.   By 1980, over 80% of households contained a color TV and about 50% of households held more than one TV. But starting at about 1980, additional changes occurred in American households concerning television viewing. At about 1980, the percent of houses wired with cable television was only 20%, but by the year 2000, this percent increased to 70%. Also about 1980, remote controls and video cassette recorders (VCRs) started to appear in homes. By 1990, already 70- 80% of households contained remote controls and VCRs. In a 10 year period starting in 1980, the way Americans watched and utilized televisions and related equipment became much more sophisticated and diverse.

The VCR data is especially interesting and relevant to me because one of my favorite stories from when my son (born in 1988) was small was that he developed an English accent because he had watched the film, Mary Popins, so many times. He also watched TV, but he especially liked to watch “Disney” movies that were becoming available on video cassette. The data on wired cable television shows that households began to receive many more stations than the locally available broadcast networks provided. The VCR and cable data accentuates the concept that the role of television in the home includes much more than just watching network programming. Also, viewing sporting events became much easier as sports only programming appeared. For example, ESPN was launched in September 1979 and has steadily increased in popularity. Since the birth of ESPN, sports only networks have proliferated on cable television.

By 2007 the average American home received 119 channels including 17 broadcast TV stations (Nielsen).

http://www.nielsen.com/us/en/press-room/2008/average_u_s__home.html

There is quite a substantial literature concerning the effects of watching television on the activity levels of children and adults. I will refer to some of these studies below. But just observing how television and all of its connecting media suddenly expanded in complexity leads to the straightforward hypothesis that physical activity was strongly curtailed by all the extra time spent watching media in the home.

If this was all that happened during this time period, Americans maybe could have adapted to the lower activity levels that accompanied the explosion in television viewing. But another very large technological advance occurred at this time that would have great effects on both home life and work in the office.

Computers in our lives

When I was writing my Ph.D. thesis in 1982, I would write in the library using paper and pencil during the day and later type what I had written using a typewriter at night when it was quiet in the lab. A colleague from my lab was also writing his Ph.D. thesis at the same time. However, he was using a desk top computer that had just become available in Madison, Wisconsin. The computer he was using was the Apple IIe. I was jealous of him but there was nothing I could do because there were no other similar computers in our entire building. Interestingly, we both completed our writing in late fall 1982. Therefore, I remember quite vividly when desk top computers became routinely available for practical writing purposes.

In the figure below the production and shipping of desk top computers is shown from their introduction to 2011.

The figure shows by 1995 a little under 50 million computers were being shipped per year. Again I have a personal recollection of this time as my 5-year old daughter (born in 1991) had mastered all of the computer game programs that were available for the Macintosh computer in our local library. The library owned fifteen different programs for children and my daughter could sit in front of the computer for several hours without lifting her head. Before my eyes I was seeing the amazing mesmerizing capabilities of the desk top computer. Therefore, by approximately 1995, there were fairly sophisticated games that could be played by children for hours and hours. I was there and personally observed it!

The figure below breaks up the different kinds of computers that were made during this period. The data plotted in this graph shows the introduction of computers during the first years of the personal computer.

The figures below show the times that were spent watching television versus surfacing the Internet by computer in the English adult population in 2006. The data, collected by IBM, show that respondents used the Internet more hours per day than they watched television. The researchers suggested that part of the reason for this observation were the extra hours used to surf the Internet during personal time at work.

There are many studies that describe the effects of the increasing use of electronic media on physical activity and health. The above figures show that the influx of all the possible ways to spend time using electronic media led to a convergence of effects such that we have been transformed to a largely sedentary society.

Tremblay and colleagues performed a systematic analysis of 232 studies with almost 1 million children. The authors concluded,

“Qualitative analysis of all studies revealed a dose-response relation between increased sedentary behaviour and unfavourable health outcomes. Watching TV for more than 2 hours per day was associated with unfavourable body composition, decreased fitness, lowered scores for self-esteem and pro-social behaviour and decreased academic achievement.”

In the same article the authors related that Intervention studies showed that many of the above negative effects were reversed when children spent less than 2 hours per day viewing television.

Mark S Tremblay, Allana G LeBlanc, Michelle E Kho, Travis J Saunders, Richard Larouche, Rachel C Colley, Gary Goldfield and Sarah Connor Gorber. Systematic review of sedentary behaviour and health indicators in school-aged children and youth.

Online open access:   http://www.ijbnpa.org/content/8/1/98

Increased television availability not only decreased daily physical activity, but it also affected sleep was in children. The presence of television sets in the bedrooms of children was observed to significantly shorten their nightly sleep time (2014).

Elizabeth M. Cespedes, Matthew W. Gillman, Ken Kleinman, Sheryl L. Rifas-Shiman, Susan Redline and Elsie M. Taveras.  Television Viewing, Bedroom Television, and Sleep Duration From Infancy to Mid-Childhood; Pediatrics 2014;133: e1163–e1171

http://pediatrics.aappublications.org/content/133/5/e1163.full.html

Convergence of Use of Digital Media on Sedentary Behavior in the US

The Centers for Disease Control (CDC) collects yearly data concerning inactivity throughout the United States. The CDC data are remarkable, and one can easily go to the CDC website in order to view PowerPoints that show the year by year increases in inactivity, as well as the increases in the obesity rates and the increases in the number of diagnosed cases of Type 2 Diabetes.

Website: http://www.CDC.gov/diabetes

I was amazed how the maps for the different parameters had similar distributions showing the areas of high incidence of inactivity and disease throughout the US. On the next slide, I placed the distribution maps for inactivity, obesity, and diabetes on the same slide. The similar distributions are eye opening!

In the following slide, seven regions with extremely high inactivity are demarcated:

Close up of Inactivity Map:

The seven areas indicated on the map are summarized here:

1.The states of Louisiana, Mississippi, Alabama, Tennessee, Kentucky, and West Virginia have high rates of inactivity, obesity, and Type 2 diabetes.

2.Eastern Kentucky and most of West Virginia have extremely high rates of inactivity and obesity (See map close ups bellow).

3.Eastern Oklahoma has a dense area of inactivity, obesity, and diabetes.

4.There is narrow strip in western Arizona and southern Utah that represents the location of various Native American tribes that have high rates of inactivity, obesity, and diabetes.

5.Northern Maine has a region of overlapping high rates of inactivity, obesity, and diabetes.

6.There is a elongated region of central California that represents the central valley that has overlapping high rates of inactivity, obesity, and diabetes.  There is much less inactivity along the coast.

7.The one bright spot in the country is Colorado, where there are light areas for all the parameters, thus relatively lower rates of of inactivity, obesity, and diabetes, compared to all other regions of the US.

The maps (from 2008) depict extremely strong data that point convincingly to the role of inactivity in the obesity epidemic.  Why are these areas especially prone to inactivity and obesity?  The answers are complex and differ from state to state and area to area.  Obesity is also the result of other factors such as healthy food deserts and an obesogenic built environment.  Some of the possible non-nutrition reasons for the high rates of low inactivity are listed below:

1.High inactivity in areas of the deep South may be due to high summer temperatures and humidity, forcing people to stay indoors in air conditioning.

2.High summer temperatures and humidity may be the reason for high inactivity in Eastern Oklahoma and Eastern Kentucky and most of West Virginia, too.

3.Northern Maine may have the opposite situation where the very long, cold winters keep people inside.

4.The narrow strip in eastern Arizona is populated by native American tribes that live on reservations that are located in areas with extremely high summer temperatures.  In addition, it is well known that Native Americans have “thrifty” metabolism that leave them susceptible to obesity on a “western type diet.”

5.The State of Colorado is a region of higher relative activity and, therefore, is somewhat resistant to the increase in obesity found in other areas of the US.

Conclusions:

It is true that all of the data presented in this chapter consist of associations.

But starting in the the 1970s and 1980s very large eruptions occurred in our society that led a large percentage of individuals, especially children, to change such that our country went from a population that performed moderate physical activity to a population that was largely immovable and sedentary.

The unmistakable conclusion that can be extracted from all the data that were presented in this chapter is that a significant portion of the increase in obesity, starting in about 1970, was the result of waves of advances in digital media and the adoption of these in every aspect of life. Of especial importance was the introductions of cable TV, VCRs, and the remote control device, which collectively led to more sophisticated media viewing. Then barely fifteen years later, the infusion of desktop computers, such that by the year 2000, most households had both sophisticated television systems and easy to use desk top computers available for attention addiction. The introduction of each of these two major digital systems caused a powerful assault on the biology of the human, such that the energy regulation system that was developed over millions of years of evolution was completely overloaded within a short 20-30 year period.