Book Reviews

October 4th, 2009 by MorganDowney Leave a reply »

THE WORLD IS FAT by Barry Popkin (Aver, New York, 2009)

Barry Popkin is a highly respected obesity researcher and professor of Global Nutrition at the University of North Carolina, Chapel Hill. In this book has given us all an insight into his life’s work – understanding the spread of obesity throughout the world.

Popkin’s work is a reader-friendly effort to tackle our persistent, modern problems of obesity: How did we get to this state? What’s the role of the food and beverage industry? What are the influences of evolution and our genes on obesity, as well as food marketing. Specifically, how did the world so quickly change its consumption patterns from long-standing local cuisines to foreign, highly-packaged, highly processed foods. Where other authors have dealt with some of these topics in great detail, Popkin’s humanizes the issues by looking at four typical families in different parts of the world and observe the change in consumption and activity.

His statistics are staggering: the average American drinks sugar-sweetened beverages about 2.5 times a day. More than 450 of a person’s daily calories come from beverages – 40% from soft drinks or fruit juices and 20% from alcohol; a slice of pecan pie, about 500 calories, would take an average adult 2.5 hours of walking or an hour of vigorous aerobics to work off.

Reading Popkin, one wishes for more international studies as countries vary in areas such as TV viewing, food advertisements. He writes, “It isn’t possible to link changes in fast-food intake in these (developing) countries with increases in obesity. However, the shift toward on-the-go eating as opposed to the slower eating of the past is a profound change. The lack of conclusive research on how Western or local fast-food chains are affecting the quantity and quality of food and the overall weight gain is a sharp contrast to the very large number of studies on this topic in the United States.”

The entire world is experiencing what is called “nutritional transition” which involved changes in occupational, lifestyle, transportation as well as nutritional factors. However, there are definite social , cultural, racial and ethnic differences. Disentangling this complex web may well be beyond any one book and it is a shame that international research organizations have not done more to explore these differences. They represent a natural laboratory which is perhaps no longer feasible within the United States because we have so many confounding factors.

This nutritional transition is of nearly unprecedented dimensions, second maybe only to the discovery of cooking or the beginning of agriculture. No wonder Gina Kolata, in her book, Rethinking Thin, The New Science of Weight Loss and the Myths and Realities of Dieting (Farrar, Straus and Giroux, New York, 2007) observed, “Some scientists, including obesity researchers like Jules Hirsch and Jeff Friedman, suggest an intriguing hypothesis. The origin of people’s recent weight gains may have little to do with their current environment or with their willpower or lack of it, or with today’s social customs to snack and eat on the run or with any other popular belief. Instead, they say, we may be a new, heavier human race and our weight may have been set by events that took place very early in life, maybe even prenatally.”

Popkin is active not only in research but in numerous governmental and non-governmental agencies across the globe trying to find strategies to affect global obesity. He offers numerous anecdotes on the efforts of these groups to find solutions. But one comes away with the view of our genetic preferences for sweet and salty foods combining with a vast industrial agricultural process fueled by aggressive and effective marketing creating a tsunami of obesity which is engulfing the world. In the end, one wishes Popkin will go on and explore the development of obesity around the world in even more depth to help us find a way out.

THE EVOLUTION OF OBESITY by Michael. L Power and Jay Schulkin, (Johns Hopkins University Press, Baltimore, 2009)

If Popkin’s book is for the general reader, this tome by Power and Schulkin is for the serious student of evolutionary biology. Popkin gives a chapter to the evolution of the modern diet; these authors give 13. They, senior researchers at the American College of Obstetricians and Gynecologists, take the long view.

Some may wonder why researchers at the home of obstetricians and gynecologists should be addressing obesity. They should not wonder. Body weight is highly regulated to be ‘just right.” Either extreme – underweight or obesity – creates problems for reproduction and survival. As a species, our bodies are interested in surviving to pass on our genes to the next generation and extreme variations in weight impede this genetic imperative.

For those confused about stories on mortality and overweight, the authors clarify that human babies are among the fattest of all mammals and this may have conferred a key support to our survival. Extra fat confers some benefits for mortality but increases other risks. But the authors definitely do not argue that obesity per se was adaptive. They argue, convincingly in my view, that “human obesity is an inappropriate adaptive response to modern living conditions.” And, “Adipose tissue is an endocrine organ whose natural function allows it to greatly increase in size; adipose tissue is meant to be variable. However, the extent of adiposity that is possible in today’s world exceeds the normal adaptive range of endocrine and immune function.”

For those who think that there is a simple answer to obesity …eat less, exercise more…this book will not provide support. The authors note, “Energy intake and energy expenditure are simple concepts in principle but very complex in actual physiology. The simple solution for weight loss, eat fewer calories and expend more, can be very difficult to achieve, for good metabolically adaptive reasons.”

But their main thesis is that fat is important both in our diets and in our bodies which likely arose in order to support the development of larger brains. “This hypothesis, “ they aver, “explains our fat babies, which explains the tendency for women to put on more fat than men do. “

The general reader may find this book too detailed but for the serious student of obesity it is a unique resource of research on every aspect of obesity in both human and animal subjects.

My only problem with the book is that they minimize the chances for drugs to treat obesity given the complexity and redundancy of the biological system to preserve body weight. They note and, given the history of obesity medications it is hard to refute them, that, “ The complexity of an evolved biological system suggests that most simple molecular interventions will have multiple unintended consequences and may trigger compensatory metabolic systems.” Fair enough. But don’t medications for blood pressure control, control of blood glucose or many other drugs have similar complexities to deal with? Why would a drug to decrease excess adiposity seem infeasible when we have several s drugs which increase adiposity? And if bariatric surgery apparently results in long term and significant weight loss without the expected unintended consequences why can’t we find the mechanism and build a drug to do the same thing?

The science is changing so fast in this area that we only hope that this is the first of a series of books allowing us to understand what is happening in our world, and our bodies.

THE END OF OVEREATING by David A. Kessler, MD (Rodale, 2009)

David Kessler’s tenure as the commissioner of the Food and Drug Administration (under Presidents George H.W. Bush and Bill Clinton), where marked by great leadership in the efforts to combat tobacco smoking.

The book should be looked at, as with Caesar’s description of Gaul, as coming in three parts. In the first part, Dr. Kessler explores the evolutionary preference humans have for sweet, fatty and salty foods.

In the second part, he deals with the food industry’s ability to take advantage of these natural likings now part of our brain patterns. The skilled, finely honed marketing machines are derided and blamed for forcing us into what Dr. Kessler calls, “conditioned hypereating” resulting in obesity.

Before you know it, the weight has piled on and your diets have all failed. Just before you throw up your hands in surrender at the nearest Cinnabon, the good Dr. Kessler has a remedy…his trademarked Food Rehab tm diet – the third phase of the book.

On page 207, the good Dr. Kessler states, “The elements of the Food Rehab tm program here have been used and tested in other contexts and still need to be rigorously evaluated for the treatment of “conditioned hypereating. “Nonetheless, I believe they can offer you some help.” The help the Food Rehab tm diet provides is “to change the way you eat.”

Let’s stop here. First, does Dr. Kessler have a reference for ‘tested in other contexts?” Well, no. Even the food companies first test a product in the lab. Shouldn’t a respected physician do the same?

For the statement “change the way you eat,” there is a citation to an abstract by Gary Foster, Ph.D, which states that, “cognitive behavioral therapy achieves about a 10 percent weight loss over twenty to twenty-four weeks with patients regaining one-third of their weight at the one-year mark.” This is left out of the main text. Isn’t this the same failed diets he just decried?

By going down the path of a “new” diet plan, Dr. Kessler has forgone the opportunity to make a real contribution to exert the kind of leadership he showed with smoking for the obesity issue. Many people feel smoking and obesity are parallel conditions and many believe that the tools which were successful in smoking cessation can work in obesity. Others note profound differences between the two problems and doubt that all of the solutions to smoking are likely to work in obesity.

Although he doesn’t know it, Dr. Kessler and I crossed paths on this topic – at least on paper. In 1999, the Internal Revenue Service reversed position and allowed the costs of smoking cessation programs to be deducible as a medical expense. In my position at American Obesity Association, I wrote a letter to the IRS asking that they also reverse their policy on not allowing the costs of weight loss to be deductible which had been issued about the same time as the smoking cessation ruling.

The IRS wrote back and said what evidence they would need to reverse their ruling. But they also said that we could not rely on their smoking cessation ruling because nicotine was addictive and cited an extremely influential study Dr. Kessler had written on the subject. (Kessler, DA, et al, The Legal and Scientific Basis for FDA’s Assertion of Jurisdiction Over Cigarettes and Smokeless Tobacco, JAMA, 1997;277:405-409)

In this paper, Dr. Kessler established that nicotine is a psychoactive (mood-altering) product and that nicotine “plays a role in weight regulation, with substantial evidence demonstrating that cigarette smoking lead to weight loss.” So I told the IRS that, on the basis of this argument, we were not going to argue that eating was addictive, but they could not argue it isn’t. (At the end of the day, we got the IRS to reverse its policy.)

Since then there has been a new research on the brain activity in smoking, obesity and alcohol consumption. Brain serotonin 2A receptor binding: relations to …[Neuroimage. 2009] – PubMed Result. Another study found, in rats, the nicotine exposure prenatally affected endocrine development and led to obesity. Prenatal nicotine exposure alters early pancreatic…[Endocrinology. 2008] – PubMed Result

There are so many questions relating to our understanding of smoking, nicotine addiction and obesity that it is a shame not to have Dr. Kessler’s expertise help lead us out of this quagmire.

CATCHING FIRE: HOW COOKING MADE US HUMAN by Richard Wrangham (Basic Books, New York, 2009)

This brilliant and readable book offers a new hypothesis about evolution of humans and the role of cooking and meal preparation. Wrangham is a professor of biological anthropology and this book shows his facility with the biological evolution of animals in general and primates in particular. More importantly, this book has several important insights into the evolution of obesity.

Briefly, Wrangham argues, pretty successfully in my opinion, that the shift from raw to cooked foods was the key factor in human evolution. Briefly, when early man began using fire, humanity started.

The process he lays out is fascinating. Once Homo Habilis (a chimpanzee like primate) evolved in to Homo Erectus, the species could shrink its digestive system, allowing humans to grow greater brains. Getting the gut to shrink depends on moving from raw food to first pounded meat and then to cooked food which were more pleasurable and digestible. This let early humans to lose tree climbing skills but gain speed in running. Speed in running allowed these first humans to run off predators who quickly overheated because of their body fir. Humans could lose body hair because fire helped them keep warm. Cooking also brought on the division of labor between men and women but promoted male-female bonding, created the household, and even led to the development of nicer people.

There are a couple of interesting aspects of this anthropological view of obesity. Wrangham devotes a fair bit of space to taking on the raw-food advocates. This movement tries to urge people to ‘return’ to the Paleolithic diet which stresses eating raw fruits and vegetables and less grain, beans and potatoes as well are refined or processed foods. Wrangham points out that, in the three studies of raw food consumption, a significant amount of body weight was lost. But there was a price. Constant feeling of hunger was one. The other was such serious energy depletion that fully half of the women in the studies stopped menstruating. Wrangham argues that a primitive society could not have sustained such depletions of energy. Further, he points to studies showing that most animals prefer cooked over raw foods.

Another interesting aspect of the authors work is that soft foods lead to an increase in obesity because fewer calories are burned in the digestive process than is the case with harder foods. (p.77)

He also express support for a more rapid change in evolution than many believe. He notes, “ ..in response to a major change in diet, species tend to exhibit rapid and obvious changes in their anatomy. Animals are superbly adapted to their diets, and over evolutionary time the tight fit between food and anatomy is driven by food rather than by the animal’s characteristics.” (p.89) Later, he cites the Grants studies of finches in the Galapagos to indicate that, if the ecological change is temporary, the changes in the species’ anatomy are also temporary. But if the ecological change is permanent, “the species also changes permanently, and again the transition is fast.” (p.93) (The work of the Grants was brilliantly described in the Pulitzer Prize winning book, “The Beak of the Finch: A Story of Evolution in our Time” by Jonathan Weiner.) He goes on to state, “The adaptive changes brought on by the adoption of cooking would surely have been rapid. “(p.94)

Further, he describes that shrinking the gut increases the size of brain and therefore intelligence. But some animals do not evolve into larger brains. Why? He answers, “Diet provides a major part of the answer…For an inactive person, every fifth meal is eaten solely to power the brain. Literally, our brains use up around 20% of our basal metabolic rate – our energy budget when we are resting – they though they make up only about 2.5 percent of our body weight. “ (p.109)

In his last chapter, Wrangham has some disquieting news for calorie-counters, the foundation of most all weight loss strategies. Wrangham goes through in some detail how Wilbur Olin Atwater came up with the caloric content of protein, fats and carbohydrates and then specific foods. And he documents the refinements in the Atwater system. The formula attributes protein with 4 calories, fats 9 and carbohydrates 4 per gram.

Wrangham spots two problems. First, the Atwater system does not recognize the energy-cost of digestion. Although humans pay less in calories for digestion than other species, it is still significant and can be reduced or increased depending on the food type: protein costs more to digest than carbohydrates and fat has the lowest digestive cost of all. He cites a 1987 study in which people eating a high-fat diet had the same weight gain as others eating almost 5 times the number of calories in carbohydrates. Also, he notes, “ Based on animal studies, we can expect that the costs of digestion are higher for tougher or harder foods than softer foods; for foods with larger rather than smaller particles; for food eaten in single large meals rather then in several small meals; and for food eaten cold rather than hot. Individuals vary too. Lean people tend to have higher costs of digestion than obese people. Whether obesity leads to a low cost of digestion or results from it is unknown. Either way, the variation is important for someone watching his or her weight. For the same number of measured calories, an obese person, having a lower digestive cost, will put on more pounds than a lean person. Life can be unfair.” (p.203) (Thanks doc, we needed that.)

Take away: nutrition scientists know the current calorie information is wrong; but it is too expensive and difficult to fix it. Net for dieters: You’re screwed – even the most rigorous calorie counter is doomed to a high error rate. Wrangham concludes, “The data in standard nutritional tables assume that particle size does not matter and that cooking does nothing to increase the energy value of foods, when abundant evidence shows the opposite to be true…We become fat from eating food that is easy to digest. Calories alone do not tell us what we need to know.”(p.205)

Overall, this is an exciting read. I know of only one other book by anthropologists on obesity (Fat, The Anthropology of an Obsession edited by Don Kulick and Anne Meneley, Jeremy P. Tarcher/Penguin, 2005) . These works show the valuable contributions to obesity we can look forward to from the work of many disciplines.

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