A Small Step for Obesity but a Great Leap in the Wrong Direction for Mankind

Abstract

Recently, the Joint Task Force of the American Society for Nutrition (ASN), Institute of Food Technologists, and International Food Information Council, proposed the de-facto globalisation of a ‘small changes’ approach to address the worldwide problem of obesity [1]. The basis of their argument was that ‘obesity rates are increasing because of a gradual weight gain in most populations,’ existing attempts to address obesity through so-called lifestyle changes have not succeeded, therefore for the present the alternative should be to focus not on achieving weight loss, but on promoting small changes in diet and physical activity to prevent further weight gain. By adopting this strategy, the Task Force argued, obesity rates would be ‘stabilised’ and over time decrease gradually. In attempting to define what is meant by small changes, Hill et al. [2] have suggested that minimal measures such as 2,000 more steps per day walking, expending only 100 kcal or substituting diet soda for a regular soda, which would eliminate 150 kcal per 340.2-g serving, might offer a ‘more sustainable’ strategy than the greater efforts necessary for permanent weight-loss maintenance. The problem is more complicated in children for whom a small energy surplus is necessary for growth. Preventing overweight in growing children may involve limiting this energy surplus to 46–72 kcal/day [3]. It would be a bold claim for even seasoned nutritionists to suggest they could monitor their personal energy equilibrium with such accuracy. Yet, the Task Force proposal suggests: ‘Small changes in diet and/or in physical activity, which might still fall short of optimal diet and physical activity recommendations, might be sufficient to stop the gradual weight gain of individuals and populations.’ Apart from some sweeping assumptions about the likely effectiveness of small changes, if taken seriously, this approach would necessitate the acceptance of an already high prevalence of obesity, not merely in the USA but worldwide, as a new ‘stabilised’ norm with all its consequences in terms of co-morbidities. With little or no evidence available to date to show how effective the ‘easy option’ approach might turn out to be in the USA, it seems somewhat premature, if not more than a little audacious, to suggest that the rest of the world – already committed in principle to the WHO global strategy on diet, physical activity and health [4] – should relax and adopt the highly speculative strategy of accepting that things continue as they are while relying on just a few little changes in the hope of avoiding further worsening in the situation. There are many factors influencing both population mean weight gain and obesity. First documented more than half a century ago, the migration of rural populations to the cities of South Africa prompted concerns about the adverse impact on health of the urban diet, and for several decades, the black African female population of the Cape Town region has suffered an obesity prevalence comparable to that in the USA [5]. In China, overweight and obesity affects 260 million adults [6], in Russia 1 in 5 women is obese [7], and in selected Middle East countries, overweight and obesity rank highest in occupied Palestine with 59% of men and 71% of women affected [8] – indicative of an aetiology more complex than merely marginal ‘lifestyle’ choices, and a reminder that obesity and under-nutrition often co-exist in the same environments. With rising childhood obesity rates now setting a consistently higher baseline, adult obesity rates are already edging towards US levels in some countries. Obesity is associated with a marked range of socio-economic inequalities, particularly amongst women; in the USA this is hardly a new phenomenon [9]. In 1965, a large study found a 6-fold variation in obesity between lowest and highest SES (socio-economic status) category females in Midtown Manhattan, with a prevalence of 37% in the very lowest SES [10]. The same study revealed an obesity prevalence of 32% among lower SES males – twice the level of the upper SES group. More recently, progressive inverse gradients reflecting the association between socio-economic conditions and health including overweight have been identified among children [11]. Thus it is important to remember that obesity, as Sir Michael Marmot notes, ‘goes to the heart of the way we live as