Chapter 1 12-27 - 1. Evolution and energy: you are what you...

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1. Evolution and energy: you are what you eat 1.1. Introduction You’ve undoubtedly all read or heard that about half the adults and many children living in almost all “westernized” countries are now, in 2011, either overweight or obese. These are epidemiological data, collected via surveys of large segments of the population, and provide reasonably accurate snapshots of particular societies. There are several important questions that arise from this observation. First, what do we mean by overweight or obese? Second, is this a new or abnormal situation? Third, is this a cause for public concern? If the answers to questions 2 and 3 are yes, which is indeed the case, then the next two questions are how did we get to this state, and can we do anything about it? These latter two questions are broad and very complex, the answers are still unfolding, and they constitute the core of this book. In our opinion, there are two fundamental scientific concepts for articulating the problem of obesity: the theory of evolution and the physicochemical concept of energy . To help you keep these cognitively accessible, think of them as “E and E” . Don’t worry - you don’t need to be an expert in either of these disciplines in order to understand obesity, but you do have to have a basic or working idea of the main concepts. The first chapter is devoted to introducing these concepts which then will become pervasive themes in or behind most chapters of this book. 1.2. Evolution Our human species, homo sapiens , has roamed our planet for about 200,000 years. During that time, we have developed complex societies, cultures and technologies. The latter two are what distinguish homo sapiens from their long-extinct evolutionary ancestors, as well as from other species of animals currently in existence. Archaeological findings suggest that from the
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earliest times humans asked questions concerning the origin of life and the concept of mortality. These and many other questions were historically considered within the prevailing local context of religion and/or culture. But over the past few hundred years scientific methods have been developed to provide a universal and observation-based framework to advance knowledge, and this approach has had spectacular results. The first comprehensive evolutionary theory is attributed to Charles Darwin who in the mid- 1800s proposed that species evolve by a process he called natural selection . This means that a species will change its characteristics over time and eventually may become a new species if and only if that change allows the individuals to better exploit the environment or compete for resources and so have increased biological “fitness” when compared with their ancestors or competitors. By so doing, they survive longer and produce more offspring, and these traits are heritable. Most scientists, including psychologists, are convinced by the overwhelming evidence that modern humans, and all creatures living, are the present day “editions” of natural selection. The ultimate mechanism for heritability lies in
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This note was uploaded on 02/12/2011 for the course PSY 4930 taught by Professor Rowland during the Spring '08 term at University of Florida.

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Chapter 1 12-27 - 1. Evolution and energy: you are what you...

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