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McKinsey Global Institute

http://www.mckinsey.com/Insights/Economic_Studies/How_the_world_could_better_fight_obesity?cid=other-eml-alt-mgi-mck-oth-1411

 

GO TO WEBSITE LINK ABOVE TO CLICK TO FULL REPORT & EXECUTIVE SUMMARY.

How the World Could Better Fight Obesity

 

November 2014 | By Richard Dobbs, Corinne Sawers, Fraser Thompson, James Manyika, Jonathan Woetzel, Peter Child, Sorcha McKenna, and Angela Spatharou

 

Box 1. The complex causes of obesity

 

 

 

 

 

The root causes of rising obesity are highly complex, spanning evolutionary, biological, psychological, sociological,

economic, and institutional factors. The UK government Foresight research on obesity identified more than 100

variables that directly or indirectly affect obesity outcomes (Exhibit 1).

 

Because of centuries of food insecurity, human beings have evolved with a biological ability to cope with food scarcity rather

than abundance. The human body seeks out energy-dense foods and tries to conserve energy as fat. Hormones that regulate

hunger and satiety encourage people to seek extra food when food is scarce but do not seem to have the ability to prevent

over-consumption or encourage extra calorie burning when food is abundant. Modern life makes fewer physical demands on many  

people, who lead less active lifestyles as technology replaces the need for physical labor. With many jobs now sedentary, exercise

is a conscious and optional choice.

 

As an illustration of the change, in 1969 about 40 percent of US schoolchildren walked or rode their

bikes to school; by 2001, only 13 percent did.1 Over the past 50 years, it has been estimated that a reduction in

occupation-related physical activity in the United States has reduced the daily net energy balance by 100 calories

per person, a significant share of the overall change in the energy balance during this period.2

 

Mass urbanization in many regions—the global urban population is growing by 65 million a year, the equivalent of

adding seven new cities the size of Chicago every 12 months—is boosting incomes but reinforcing a less physical

lifestyle.3 One Chinese study found that urbanization reduces daily energy expenditure by 300 to 400 calories, and

traveling to work by car or bus reduces it by a further 200 calories.4

 

Human beings also have a psychological relationship with food that goes beyond a need for basic sustenance.

Many of us use food as a reward or to relieve stress, or have a compulsive relationship with certain types of food.

There is a correlation between obesity and high rates of some mental health conditions, including depression.

1 Noreen C. McDonald, “Active transportation to school: Trends among US schoolchildren, 1969–2001,” American Journal of

Preventative Medicine, volume 32, issue 6, June 2007.

 

2 T. S. Church et al., “Trends over 5 decades in US occupation-related physical activity and their associations with obesity,” PLoS ONE,

volume 6, number 5, 2011.

3 For more on urbanization, see, for example, Urban world: Mapping the economic power of cities, McKinsey Global Institute,

March 2011.

4 W. P. James, “The fundamental drivers of the obesity epidemic,” Obesity Reviews, volume 9, supplement 1, March 2008.

 

Academics have emphasized that obesity is a systemic problem:

causes are complex, manifold, and interdependent

Obesity causal map

SOURCE: B. Butland et al., Foresight: Tackling obesities—future choices, UK Government Office for Science, project

report, 2nd ed., October 2007.

Exhibit 1

Media Social Psychological Economic Food

Activity Infrastructure Developmental Biological Medical

Positive influence

Negative influence

Overcoming obesity: An initial economic analysis 13

 

McKinsey Global Institute

 

Box 1. The complex causes of obesity (continued)

People are highly influenced by social norms and subtle social cues in their eating habits and their attitude toward

weight. For instance, if they dine with other people who eat more, they eat more themselves; likewise, those who

dine with people who eat less, eat less themselves. One study has shown that 35 percent more calories are

consumed when having dinner with a friend than when eating alone, and 96 percent more if dining in a group of

seven people.5 Another study has shown that a person is 57 percent more likely to become obese if a friend has

also become obese—evidence of social normalization of the condition.6

 

Food has become much more affordable over the past 60 years. In the United States, the share of average

household income spent on food fell from 42 percent in 1900 to 30 percent in 1950 and to 13.5 percent in 2003.7

This is beneficial in welfare terms, reducing rates of undernutrition and freeing up disposable income.

Many of these factors underline the importance of the environmental context as a driver of obesity prevalence.

A helpful lens for examining how the environment affects prevalence is looking at expatriate populations,

transplanted from one context to another. For example, British expats who have settled in Abu Dhabi have

diabetes prevalence rates of 18 percent, compared with a baseline prevalence of 8 percent in the United Kingdom.

Physical environment is one factor, but it is likely that sociocultural variables are also relevant. Various studies

suggest a correlation between Hispanic immigrants’ obesity rate and the length of their stay in the United States

and the depth of their cultural assimilation.8

 

Some experts are questioning whether the net energy balance—that people are eating too much and exercising

too little—is the appropriate lens to examine root causes. There is growing interest in the role that different

nutrients such as carbohydrates, proteins, and fats play in our metabolism and in hormones that regulate satiety

and hunger. Many leading scientists support the view that refined carbohydrates promote weight gain and inhibit

weight loss.9 The science to date on this is inconclusive, and we do not include it in the assessment here without

further evidence. However, it is an important area for further research and could refocus the design of obesity

interventions. Similarly, there is increasing interest in the role of the microbiome—our intestinal bacteria ecosystem.

Scientific evidence from controlled trials suggests that individuals whose bodies contain a greater diversity of

bacterial species are less prone to high body mass index (BMI) and less likely to gain weight.10 This also is too

inconclusive for us to include at this stage.

 

Some commentators take the causal complexity illustrated in Exhibit 1 as a pre-determined defeat. They say, “If

the causes are so complex, where do we begin?” However, we do have a good understanding of the proximate

causes, even if the background causes are complex. We know that over the past 50 years, individuals’ daily

energy balance equation has changed; physical activity has declined, and energy consumption has increased.

Even though there are important outstanding questions about diet composition, gut microbiome, and epigenetics,

we are not walking blind with no sense of what to address. However, interventions to increase physical activity,

reduce energy consumption, and address diet composition cannot just seek to reverse the historical trends that

have left the population where it is today. For example, we cannot, nor would we wish to, reverse the invention

of the Internet or the industrialization of agriculture. We need to assess what interventions make sense and are

feasible in 2014.

 

5 Brian Wansink, Mindless eating: Why we eat more than we think, Bantam-Dell, 2006.

6 Nicholas A. Christakis and James H. Fowler, “The spread of obesity in a large social network over 32 years,” New England Journal of

Medicine, volume 357, number 4, July 2007.

7 100 years of US consumer spending data for the nation, New York City, and Boston, US Department of Labor, report number 991,

May 2006.

8 D. A. Himmelgreen et al., “The longer you stay, the bigger you get: Length of time in the US and language are associated with obesity

in Puerto Rican women,” American Journal of Physical Anthropology, volume 125, number 1, 2004.

9 B. J. Brehm et al., “The role of energy expenditure in the differential weight loss in obese women on low-fat and low-carbohydrate

diets,” Journal of Clinical Endocrinology and Metabolism, volume 90, number 3, March 2005.

10 Herbert Tilg and Arthur Kaser, “Gut microbiome, obesity and metabolic dysfunction,” Journal of Clinical Investigation, volume 121,

number 6, June 2011.