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McKinsey Global Institute Releases Economic Analysis on Overcoming Obesity

By Melissa An and Alexander Wolf

Twitter summary: McKinsey study estimates obesity costs world $2 trillion, society cannot wait any longer to try and implement change

The McKinsey Global Institute (MGI) recently released a valuable paper titled, “Overcoming Obesity: An Initial Economic Analysis,” which discusses the global economic impact of obesity as well as potential solutions already in place. According to the findings, 2.1 billion people (almost one third of the global population) are either overweight or obese, and obesity is responsible for roughly 5% of deaths worldwide. Obesity also causes a mind-boggling total global economic cost of $2 trillion each year. To put this into context, $2 trillion is the size of India’s economy – the 10th largest in the world! This cost also ranks as one of the top three human-generated economic burdens in the world, in line with the impact of smoking ($2.1 trillion) and armed violence ($2.1 trillion)

This report is the first ever to create a global figure for the cost of obesity and is an important first step in elevating the conversation surrounding this global crisis.  A major point is that it demands a systems-level approach, requiring collaboration among many corners of society as well as changes in our overall food and health environment and culture. The report stresses that money put into obesity prevention accounts for only 0.25% of the total cost of obesity worldwide – the vast majority of resources are devoted to dealing with obesity’s complications and consequences. In other words, we are spending far more money on dealing with the consequences of obesity than we are on preventing it in the first place.

The report analyzed 74 obesity interventions (drawing data from the UK), finding that many interventions can be cost-effective. These interventions focused in areas such as healthy meals, the availability of high-calorie foods and drinks, nutrition labeling, parental education, pharmaceuticals for obesity, portion control, public health campaigns, school curriculum on healthy lifestyles, taxes on unhealthy foods, improving the walkability of the urban environment, weight management programs, and workplace wellness, among others. This analysis found that 95% of the interventions were highly cost-effective. The authors also stressed that the most effective types of interventions were those that were more “subconscious,” relying more on changes in the external environment rather than on individual choice. For example, the report determined that the most effective measures came from reducing the size of portions in packaged foods, fast-food restaurants, and cafeterias.

It appears that the only specific obesity drug given even a brief mention is Novo Nordisk’s liraglutide, which is still under FDA review (though we expect approval shortly). Bariatric surgery received only a few mentions; though many experts believe it may be a promising avenue to learn more about the mechanisms of obesity (learn more here), it certainly isn’t a mass solution.

The authors advise that as a society, we cannot wait for better data on effectiveness and cost of obesity-prevention initiatives to implement change. Many obesity interventions – for example, taxing sugary beverages – are often criticized for not having enough evidence to show that they will actually work. The McKinsey report advises to not let these concerns prevent new interventions from happening, advocating for an aggressive all-hands-on-deck approach. We agree, and believe there is opportunity to try small experiments, validate interventions, and scale them up to improve public health.

We had the chance to poll a number of key opinion leaders in obesity on their reactions to the report. While we found a general consensus that the report did a very good job of highlighting the complexities of obesity prevention, several leaders did point out shortcomings in the report. For example, though The Economist provided overall positive coverage of the discussion paper, it commented that “it focuses on behavior, rather than clinical questions such as the role of specific nutrients or genetics in obesity” and that the report “glosses over disagreement about what makes people fat.”

  • Dr. Donna Ryan, a highly respected obesity researcher, professor, and the Associate Executive Director for Clinical Research at the Pennington Biomedical Research Center (Baton Rouge), expressed her wish that the report did more to acknowledge the biology underlying obesity. She stated that the report is a “double edged sword,” and that while it is “extremely valuable in cutting right through to the problem and the global burden of the disease [obesity],” it relies too heavily on the assumption that obesity is the result of personal choices or responsibility without deeply considering its biological causes. 

  • Dr. Arya Sharma also discussed the report, stating on his website that the authors fall into the common misconception about obesity simply being a matter of calories in and calories out, “a balance that can be volitionally adjusted to achieve whatever body weight you wish to have.” If anything is clear in nutrition and obesity research, it’s that losing weight is anything but simple. While energy imbalance is the cause of obesity, it remains unclear what exactly causes that energy imbalance, and it likely involves many different complex biological mechanisms. Furthermore, and equally important, as explained in the landmark paper, “Energy balance and its components: implications for body weight regulations,” aspects of the body’s metabolism change over time with fluctuations in body weight. Thus, any energy imbalance (e.g. greater energy output than intake which initially leads to weight loss) then triggers compensatory mechanisms, such as changes in resting energy expenditure (the amount of energy used by the body during resting conditions) and the secretion of hormones that regulate satiety (feeling full) and hunger. In other words, when energy imbalance occurs, the body responds in complex ways to bring a person’s weight back to its previous level. That means the number of calories consumed or expended during a period of weight change affects body weight differently than the same calories consumed/expended when weight is stable over a long period. It’s not simply the absolute number of calories we ingest - it’s how the body metabolizes those calories that will impact weight. Dr. Sharma also warns that the report’s recommendations to essentially “try anything” may give people a “free pass” to implement intervention programs “without having to demonstrate that what they did, had any effect at all.” 

These and other critiques are all important in moving toward some type of framework to address the problem.  Disagreements are inevitable, but at minimum, the McKinsey Global Institute report has made clear that the global costs of obesity have made the price of inaction too high to bear.

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