‘Leanwashing’ – and its Role in the Obesity Crisis


What makes you fat? Ask the ordinary man or woman in the street and many will respond, “eating too much,” but significant numbers will cite “lack of exercise.”  Medical research, however, has established that the main determinant of the obesity crisis is overeating. So why does the popular misconception of lack of exercise persist – and why does it matter?

The obesity crisis cannot be ignored. In 1980, less than 10% of populations in industrialized countries were classified as obese; these rates have since doubled or tripled. Obesity is a major risk for hypertension, type-2 diabetes, coronary heart disease, stroke, osteoarthritis, respiratory problems and certain types of cancer, and outranks smoking and drinking in its deleterious effect on health and health costs. There is no suggestion that exercise is a waste of time: it has a positive effect on health and well-being and increases longevity, and helps to some extent in weight loss and maintenance. But it is not a “cure all”: a Starbucks Venti Java Chip Frappuccino contains 580 calories – you would have to walk for four hours just to work off this one drink.

Researchers Aneel Karnani, Brent McFerran and Anirban Mukhopadhyay have been investigating what they call “lay theories of obesity”, and conducted six surveys in four countries to determine the relative importance of overnutrition versus lack of exercise as the causes of obesity in lay theories. They discovered that only about half of lay people believe bad diet to be the primary cause of obesity. In addition, they found those who mistakenly underestimate the importance of diet are, in fact, more likely to be overweight. The authors devised the term “leanwashing” to describe the effect on the general public of the marketing and public relations campaigns of food and beverage companies that overemphasize the role of lack of exercise in obesity.

The sources of lay theories related to obesity are multiple, but corporate messaging is one of the most prominent. The research team identified public statements, lobbying, exercise philanthropy and sports sponsorships by the food industry as having an indirect effect. Companies claim to be helping tackle the problem of obesity, but the message is not unbiased, and is inconsistent with scientific evidence: “poor diet” is hardly mentioned, while “exercises,” “choices,” and “balance” feature highly. In contrast, many public health experts and social activists call for government action, such as “sin taxes” on sugary and fat-laden foods and drinks, and restrictions on the marketing of unhealthy foods. Several countries have implemented such ideas; among those that have not, however, is the U.S. where government interventions are seen as heavy-handed and unpopular.

The researchers do not seek to take sides, but offer the argument that the food industry should be held partly responsible for the obesity crisis, even while granting the central premise of individual responsibility, and understanding that companies have a fiduciary responsibility to shareholders to increase profits.

The researchers’ view is that governments could attempt to directly educate the public about the role of a bad diet in causing obesity, through campaigns, taxation and restrictions on food advertising. Such an approach might be useful and politically pragmatic in both countries that lean towards the individual side of the scale and those that favor systemic governmental action. Not only would this increase awareness among lay people thereby helping fight the obesity crisis, but, in so doing, would also reduce the incidence of leanwashing.


Associate Provost (Teaching & Learning), Provost Office, Lifestyle International Professor of Business, Chair Professor