Systems Thinking in Circles about Obesity

Like many of my new ideas recently, other people have already written books on them. One recent idea was to draw an influcence diagram and apply a bit of systems thinking to weight management, but a quick search revealed
‘Thinking in Circles About Obesity’ by Tarek K.A. Hamid (2009, ISBN 978-0-387-09468-7) by Springer.

The first sentance is always important to set the tone of the book; ‘Today’s children may well become the first generation of Americans whose life expectancy will be shorter than that of their parents‘.

Dispite all the education programs, adverts, healthy/reduced fat foods and self help books, as a populatation we’re getting fatter. He notes that the obesity problem can be represented as a dynamic system of energy regulation to be analysed using system dynamics.

Tarek states that “This book argues for, and presents, a different perspective for thinking about and addressing the obesity problem: a systems thinking perspective. While already commonplace in engineering and in business, the use of systems thinking in personal health is less widely adopted.”
Tarek may have assumed that the wide spread use of systems engineering includes systems thinking, but if this is true then I might be wasting my time with this EngD. While my conversations to sell ‘systems thinking’ to other systems engineers usually include a lot of explaining the difference between systems thinking and requirements capture, systems thinking certainly doesn’t seem commonplace or easily recognisable as a process by another name. I do agree with the statement that the tools and concepts associated with systems thinking are ‘extremely intuitive’ and even young children can learn systems thinking very quickly (..but I just happen to be studying it at doctoral level, erm) .

Systems thinking was considered a topic for university-level education, but this assumption was challenged in the 1970s, by Professor Nancy Roberts at Lesley College who introduced the concepts of systems thinking to fifth- and sixthgrade students. The STACI (Systems Thinking and Curriculum
Innovation) project initiated early in the 1990s, examined the cognitive and curricular impact of using the systems thinking approach in precollege instruction in schools.

The problem of Weight

Most people don’t get fat over a short period, but gain weight at a low rate (half a pound per year) that may increase depending on their lifestyle. The early stages of weight gain often go unnoticed or may be viewed as a sign of inevitable maturity. In the UK, most college/sixth form studets learn to drive at around 17 and the effect at my college was dramatic as the amount of daily exercise dropped to nought. We all can(should be able to) recognise how unhealthy our lifestyles are, and while we might accept that we’ve put on a bit of weight, we all know that bits of weight add up. Tarek uses the analogy of not noticing the partners we live with age (continuous, gradual change), but notice how the relatives we see once in a while have aged.

The US Centers for Disease Control and Prevention (CDC) note that most of today’s obese adults were not obese children, accumulating their extra pounds only after they were 25 or 30 years old. The US now have nearly twice as many overweight children who are already obese at the age of 10 and almost three times as many overweight adolescents as there were in the 1980s.

The number of overweight people in the world has risen to match the number of undernourished: 1.2 billion.

Weight loss = Eat better x Exercise

Obese people are often seterotyped as having poor self-control, as weight loss is considered a simple exercise in self restraint with a bit of more exercise. Tarek rejects the assumption that weight loss is a simple discrete, one-time decision, but rather a complex dynamic series of decisions that constrain future decisions. Time delay is an additional complication removing cause from effect outcomes and making it harder to adjust behaviour.

A study by Harvard University found that most Americans are still not seriously concerned with obesity and do not view it as a major health concern either for the country as a whole or particularly for themselves. This seems counter to an given study of college students who found that the eligible bachelors and bachelorettes considered embezzlers, cocaine users, and even shoplifters where rated more suitable marriage partners than obese individuals. Tarek also states that studies consistently show that overweight job candidates are less likely to be hired than nonoverweight candidates (even when perceived to be equally competent on job-related tests) and when hired often earn less.

Simple answers to complex problems

Cognitive theorists and philosophers argue that humans tend to seek simple answers to the causes for even the most complex problems. These short-cuts are often shown to systematically lead to errors in judgment. Large portions of the book, keep re-enforcing the message that concentrating solely on individual-centric issues has limited our ability to examine and understand issues, and narrowed the focus of research into the causes of obesity. Obesity is not increasing because people are consciously trying to gain weight.

Tarek presents diagrams that show how physiology is effect by energy in/out, our behaviours and our environment. This seems to indicate a 5WH method (What, Why, Where, When, Who and How).

WHAT WE EAT – After an uncomfortable statement that ‘America’s eating habits started to change in the second half of the 20th century, when a growing number of women began to enter the labor force’, therefore meals were no longer prepared from fresh produce, the Institute of Economic Research at Harvard University states that the new roles for women turned out to be one of the most important developments affecting America’s eating habits in the past 50 years. I guess this means that American men are obese because those darn women went off to work and didn’t have time to cook dinner!
This meant that there was demand for fast convient food and snacks. In the past 30 years, an enormous number of tasty snacks have been introduced into the food market, many falling into the nutrient-poor, high energy-dense categories that are distributed through vending machines dotted around our workplaces, ensuring the availability of cheap, high-fat, high-calorie snacks. Snackers do not compensate for their sins with a reduced main meal portion size, leading to increased daily energy intake.

WHEN WE EAT – Time is money, so (unlike the French) we don’t want to waste it sitting around eating a decent meal, so we opt for a quick bite that opens the way for the need to snack later. A person on a diet is less likely to have a mid-afternoon snack if it requires a 10-minute walk to the corner store but is much more likely to have a snack if the vending machine is 10 metres away.

WHERE WE EAT – We consume more of our daily energy intake outside the home. Americans love McDonald’s and I’ve personally seen the ‘dinner run’ at about 1530-1600 when parents have picked the kids up from school and driven straight to the golden arches for tea. The time spent by an average customer in a fast-food restaurant is eleven minutes.

WHY WE EAT IT - Do you want that supersized? For a relatively small increase in price, supersizing greatly increases the number of calories we get. Food intake was 30 percent higher when given the largest compared to the smallest serving, a significant increase, prompting the researchers to confidently conclude that, ‘human hunger could be expanded by merely offering more and bigger options’.They revealed strong cultural underpinnings to our apparent compulsion to eat more when served larger portions.

Changing the Vicious to Virtuous causal loops

Positive feedback loops and processes are advocates of change because with sufficient effort, even small deviations can be amplified and result into major shift. Negative feedback loops are different in that they counter and oppose change.

Tarek states that are bodies rely on a negative feedback process to resist change and maintain stability. The act of exercise however improves fitness and the ability to exercise for longer, leading to increased energy expendature and improved fitness. Although the elements of the influence diagrams are easily recognisable (I was hoping for new found view points) the feedback loops did highlight the short and long term feedback effects.

Most overweight individuals tend to set weight-loss goals that reflect their image of what their ideal body weight should be from weight charts read in a book or magazine article. The unrealistic goals that people often set not only nearly guarantees that they cannot be fulfilled, but in fact contribute a relapse. This then creates the self-control weight loss cycle or ‘yo-yo dieting’.
A common trend is goal erosion as we adjust our ‘ideal goal weight’ to our ‘achievable goal weight’, which can cycle a few times before a complete relapse.

Conclusions

The book is not for the mainstream reader keen on a quick fix for weight loss, but is an example of moving from a simplistic view of a common problem into a realistic model (all the way down to Glucose uptake/release and feedback to insulin secretion/breakdown). I am very much a visual person and love the pretty pictures and diagrams, that were few and far between – this is a reading book.
I never saw the big holistic influence diagram that I was expecting, but was presented with a few small or combined feedback loops. For a systems thinking thesis, it doesn’t feel systemsey enough. The system boundary or model is not identified, neither are actors, elements or relationships defined to any depth. It’s not a dieting manual, but is an example of systems thinking applied to a problem.

A key takeaway message from the book is this: We cannot and should not rely on intuition alone in managing our bodies. With its many interrelated subsystems and processes (some counteracting, some reinforcing) the human body is simply too complex to effectively manage by human intuition
alone. Our bodies don’t work in straight lines!

The commoon premise is that once the public are educated, people will abandon unhealthy lifestyle behaviors. This has not been the case, as people do not want to be lectured about their bad habits. A more effective method would be to engage people through play. Tarek seems to want to lay the foundation to sell software to help manage individual weight programmes; ‘It is time to use the technology not to automate existing processes but to enable new ones’

Dr. Tarek K.A. Hamid

Dr. Tarek K.A. Hamid is a trained system dynamicist (with a PhD from MIT, and a winner of the Forrester award for his first book). He has been a Professor of System Dynamics at the Naval Postgraduate School, in Monterey, CA since 1986, where he was awarded the Naval Postgraduate School’s Faculty Performance Award, in recognition of meritorious faculty performance in both research and teaching.

In the mid 1990s he became extremely interested in the confluence of information and medical technologies, and saw it as one of the most promising new frontiers for system dynamics research and public policy. But he had a lot to learn. So, in 1997, he took an open-ended leave-of-absence and enrolled in the Master’s Program at Stanford’s Engineering Economic Systems & OR Dept., where he focused on decision analysis and medical decision-making. Read more

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Tuesday, 17th 17 Jan 2012

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