Book Review: Deirdre Barrett Waistland. The (R)evolutionary Science Behind Our Weight and Fitness Crisis. New York: W.W. Norton & Company, 2007, 320 pp. $24.95 (hbk.); ISBN: 978-0-393-06216-8

At first glance Barrett’s Waistland follows the familiar format of numerous other diet books. There is a picture of a burger on the front, a catchy title, and a photo of the slim, successful-looking author on the back, accompanied by a list of impressive-sounding credentials. So, is Barrett’s book really any different? Barrett examines obesity and exercise from an evolutionary perspective. She starts by describing what we should be eating. According to Barrett we should be eating like our hunter-gatherer ancestors of over 10,000 years ago. In other words, lots of vegetables, moderate amounts of lean protein and fruit, and small amounts of nuts, seeds and eggs. White flour, refined sugar and trans fats are most definitely not on the list. She goes on to explain why we all want to eat what we shouldn’t. Drawing on work by the ethologist Tinbergen she explains how these foodstuffs represent supernormal stimuli. Tinbergen constructed bird eggs that exaggerated the natural characteristics of real bird eggs – they were larger and had more prominent colours and markings. The birds preferred the fake eggs, often at the expense of the real ones. Barrett states that because sugars, salts and fats are relatively rare in the wild, we have evolved to the prefer them. Thus today’s burgers, sodas and doughnuts, with excessive amounts of sugar, salt and fat, represent supernormal stimuli which we consume at the expense of more natural and nutritious alternatives. It’s a similar story with exercise. Ten thousand years ago we were walking several miles a day, carrying hunting equipment and toddlers. When times were hard, those who conserved energy, by not doing very much, were more likely to survive. Thus unlike hamsters, who will happily spend half the day running round a hamster wheel, we humans have no instinct to exercise. Instead, given the choice, we are likely to do not very much at all. Television makes the situation worse. According to Barrett this is another example of a supernormal stimulus. She refers to work by Pavlov on the ‘orienting response’. This is an instinctive response to any sudden or novel stimulus, such as a sound or movement. It evolved to spot and assess food, mates, enemies and predators and involves turning in the direction of the stimulus and freezing. Barrett suggests that programming such as commercials, action sequences and music videos provoke orienting responses at a rate of one per second, maintaining our attention but overloading the system and resulting in reductions in learning, memory and metabolism. Indeed she claims that metabolism averages 14.5% lower when watching television compared to simply lying in bed. So what can we do about it? First we need to do more exercise, either by going to the gym, participating in a sport or considering a job that builds in exercise. Barrett makes some encouraging remarks about the benefits of exercise plus a few more unusual suggestions such as having business discussions whilst walking in the park. Second we need to stay away from the supernormal stimuli. Not just limit the TV, popcorn and candy but exclude them completely. Barrett goes on to compare junk food with addictive substances, suggesting that the only way to really rid yourself of cravings is to cut them out completely. More controversially she suggests we might learn a few things from people with anorexia. Whilst acknowledging the seriousness of this condition she nevertheless notes that people with anorexia ‘know how to take weight off’. In particular they are aware that it is the first couple of days of food restriction that is the hardest, after which the cravings disappear. However, going cold turkey on junk food is difficult. Barrett has two suggestions. The first is to make healthy food choices and exercise routines a matter of habit rather than as things we agonise over. The second is to practice exercising willpower. She discusses two techniques that could be used to improve willpower – cognitive behavioural therapy (CBT) and hypnosis, the latter supported by some feel-good success stories from her own clinic. Finally she talks about the importance of change at the societal level, for example cutting subsidies on foods such as white flour and butter and placing restrictions on advertising. So is Barrett saying anything new? And is this book really the answer to our ‘weight and fitness crisis’? The strength of the work lies in its insightful use of anthropology and ethology to account for our current behaviour and to suggest the kinds of eating and exercise plans that might be most beneficial for our health. Barrett’s discussion is highly readable, well-referenced and should appeal to academics and lay persons alike. However, her suggestions for change are less convincing. Whilst her recognition of the importance of psychological approaches is welcome, this section of the book felt JOURNAL OF HEALTH PSYCHOLOGY 13(7)