American Scientist

Why Geese Don't Get Obese (and We Do): How Evolution's Strategies for Survival Affect Our Everyday Lives. Eric P. Widmaier. 212 pp. Freeman, 1998. $22.95.

Contrary to its title, this book is not about obesity; nor is it about geese. Eric Widmaier uses the problem of obesity to hook us, then surreptitiously teaches us comparative physiology. In one respect, this is a clever strategy. After all, obesity commands almost as much public attention as sex. Once we have gotten past the first few chapters, he leads us on a delightful and very readable introduction to what makes animals tick, and by the time we realize obesity is beside the point, we are drawn into fascinating questions about what makes various animal species unique.

Widmaier teaches the basics of physiology by explaining how a variety of birds, fishes, reptiles and mammals managed to fill their particular evolutionary niches. He covers such diverse topics as neuroendocrine control of appetite, basic cell physiology, cardiovascular physiology, thermoregulation, salt and water homeostasis, sensory systems, learning and adaptation and evolution. All topics are deftly dealt with without oversimplifying or relying on "pop" science, providing the intelligent reader with just enough depth to come away with useful knowledge.

The theme is straightforward. The physiology of an animal evolves as an adaptation to its particular environment. The effect of food consumption on weight is used as an early example. Small animals can consume the equivalent 200 times the caloric intake of a human without becoming obese because they have very high metabolic rates necessary to keep them warm. As animals become larger, heat loss becomes less of a problem, and metabolism slows down. Some animals, like geese, overeat in preparation for migration or hibernation. They store large amounts of fat that are then used either to fuel a long voyage or provide nutrition during extended inactivity.

Although the use of obesity as a come-on may pull in some readers, others who are drawn to Why Geese Don't Get Obese by its title will be sorely disappointed. True, there is more on metabolism and feeding here than any other topic; as if to honor the implicit promise to deal with obesity, three chapters are devoted to the basics of metabolism and appetite control. But this treatment does not even scratch the surface of what science now knows about what makes some of us lean and others fat. Indeed a whole book the size of this could have been written to give the reader what was promised in the title.

The real value of Why Geese Don't Get Obese is that it provides the intelligent lay person with a terrific introduction to the science of physiology. Unfortunately, the title of this book will do little to alert those looking for such information to this one's real merits. The admonition "don't judge a book by its cover" is very applicable in this case.—Richard S. Surwit, Psychiatry and Behavioral Sciences, Duke University Medical Center