Factors That Determine What, When, and How Much We Eat

Hunger, Eating, and Health
12.1 Digestion, Energy Storage, and Energy Utilization
12.2 Theories of Hunger and Eating: Set Points versus Positive Incentives
12.3 Factors That Determine What, When, and How Much We Eat
12.4 Physiological Research on Hunger and Satiety
12.5 Body Weight Regulation: Set Points versus Settling Points
12.6 Human Obesity: Causes, Mechanisms, and Treatments
12.7 Anorexia and Bulimia Nervosa
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Biopsychology, Eighth Edition, by John P.J. Pinel. Published by Allyn & Bacon. Copyright © 2011 by Pearson Education, Inc.
source of serious personal and health problems. Most eating-related health problems in industrialized
nations are associated with eating too much—the average American consumes 3,800 calories per day, about twice the average daily requirement (see Kopelman, 2000). For
The paper must be neatly formatted, double-spaced with a one-inch margin on the top, bottom, and sides of each page. When submitting hard copy, be sure to use white paper and print out using dark ink. If it is hard to read your essay, it will also be hard to follow your argument.example, it is estimated that 65% of the adult U.S. popu- lation is either overweight or clinically obese, qualifying
this problem for epidemic status (see Abelson & Kennedy, 2004; Arnold, 2009). The resulting financial and personal costs are huge. Each year in the United States, about $100 billion is spent treating obesity-related disorders (see Ol- shansky et al., 2005). Moreover, each year, an estimated 300,000 U.S. citizens die from disorders caused by their excessive eating (e.g., diabetes, hypertension, cardiovas- cular diseases, and some cancers). Although the United States is the trend-setter when it comes to overeating and obesity, many other countries are not far behind (Sofsian, 2007). Ironically, as overeating and obesity have reached epidemic proportions, there has been a related increase in disorders associated with eating too little (see Polivy & Herman, 2002). For example, almost 3% of American adolescents currently suffer from anorexia or bulimia, which can be life-threatening in extreme cases.
The massive increases in obesity and other eating- related disorders that have occurred over the last few decades in many countries stand in direct opposition to most people’s thinking about hunger and eating. Many people—and I assume that this includes you—believe that hunger and eating are normally triggered when the
body’s energy resources fall below a prescribed optimal level, or set point. They ap- preciate that many factors in-
fluence hunger and eating, but they assume that the hunger and eating system has evolved to supply the body with just the right amount of energy.
This chapter explores the incompatibility of the set- point assumption with the current epidemic of eating disorders. If we all have hunger and eating systems
whose primary function is to maintain energy resources at optimal levels, then eating disorders should be rare. The fact that they are so prevalent suggests that hunger and eating are regulated in some other way. This chapter will repeatedly challenge you to think in new ways about issues that impact your health and longevity and will provide new insights of great personal relevance—I guarantee it.
Before you move on to the body of the chapter, I would like you to pause to consider a case study. What would a severely amnesic patient do if offered a meal
shortly after finishing one? If his hunger and eating were controlled by energy set points, he would refuse the sec- ond meal. Did he?
The Case of the Man Who Forgot Not to Eat
R.H. was a 48-year-old male whose progress in graduate school was interrupted by the development of severe am- nesia for long-term explicit memory. His amnesia was similar in pattern and severity to that of H.M., whom you met in Chapter 11, and an MRI examination revealed bilateral damage to the medial temporal lobes.
The meals offered to R.H. were selected on the basis of interviews with him about the foods he liked: veal parmi- giana (about 750 calories) plus all the apple juice he wanted. On one occasion, he was offered a second meal about 15 minutes after he had eaten the first, and he ate it. When offered a third meal 15 minutes later, he ate that, too. When offered a fourth meal he rejected it, claiming that his “stomach was a little tight.”
Hunger, Eating, and Health