The global nutrition transition, which embraces major changes in how food is produced, distributed and consumed, is associated with rapid increases in the prevalence of obesity, but the implications for diabetes differ between populations. A simple conceptual model treats diabetes risk as the function of two interacting traits: ‘metabolic capacity,’ which promotes glucose homeostasis, and ‘metabolic load’, which challenges glucose homoeostasis. Population variability in diabetes prevalence is consistent with this conceptual model, indicating that the effect of obesity varies by ethnicity. Evolutionary life history theory can help explain why variability in metabolic capacity and metabolic load emerges. At the species level (hominin evolution), across human populations and within individual life courses, phenotypic variability emerges under selective pressure to maximise reproductive fitness rather than metabolic health. Those exposed to adverse environments may express or develop several metabolic traits that are individually beneficial for reproductive fitness, but which cumulatively increase diabetes risk. Public health interventions can help promote metabolic capacity, but there are limits to the benefits that can emerge within a single generation. This means that efforts to curb metabolic load (obesity, unhealthy lifestyles) must remain at the forefront of diabetes prevention. Such efforts should go beyond individuals and target the broader food system and socioeconomic factors, in order to maximise their efficacy.
This working paper is meant to provide a quick reference guide to and portrait of the underlying principles that support current public health practice; it is not intended to be the definitive treatise on this topic. It defines the perspective that CPHA will use to develop its policy options.
This essay was delivered as a commencement address at the University of California–Berkeley School of Public Health on May 17, 2015. Reflecting on events spanning from 1990 to 1999 to 2015, when I gave my first, second, and third commencement talks at the school, I discuss four notable features of our present era and offer five insights for ensuring that health equity be the guiding star to orient us all. The four notable features are: (1) growing recognition of the planetary emergency of global climate change; (2) almost daily headlines about armed conflicts and atrocities; (3) growing public awareness of and debate about epic levels of income and wealth inequalities; and (4) growing activism about police killings and, more broadly, “Black Lives Matter.” The five insights are: (1) public health is a public good, not a commodity; (2) the “tragedy of the commons” is a canard; the lack of a common good is what ails us; (3) good science is not enough, and bad science is harmful; (4) good evidence—however vital—is not enough to change the world; and (5) history is vital, because we live our history, embodied. Our goal: a just and sustainable world in which we and every being on this planet may truly thrive.
“Natural capital’ is an understandable attempt to put a value on our living planet and all the services it provides for us, writes John McMurtry. But it fails by measuring nature in dollars and cents. We need to develop a new concept of ‘life capital’ that must be preserved from exploitation and degradation no matter… Read More