Welcome to the continuing diary series "Let's Read a WHEE Book Together!" This week, we're continuing with David Kessler's The End of Overeating, Chapter 31. If you're just discovering this diary series, you will find links to the previous installments at the bottom of this diary.
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The End of Overeating, by David Kessler, M.D.
Chapter 31: Conditioned Hypereating Emerges
In Chapter 31, Kessler further defines "conditioned hypereating," the term he introduced in Chapter 29. He also explains his reason for defining the term - after talking with people about uncontrolled eating, he found two reactions. Most people understood what he was talking about, but a smaller group had no personal experience with out-of-control eating, and thought that the problem was a lack of willpower in the obese.
To get started, I mostly had a lot of questions. What features define conditioned hypereating? Who is affected? How is it linked to excess weight? Why do some people at a healthy weight also exhibit conditioned eating behavior?
Kessler and other researchers reviewed studies that compared the eating behaviors of obese and non-obese people. Kessler references one study that found that obese Swedish women not only consumed more calories per day, but were much more likely to snack and eat more when they ate at nontraditional mealtimes than were the non-obese. Another behavior found much more common in the overweight and obese was the tendency to continue eating past the point of satiation. Another study showed that obese women were more likely than non-obese women to choose food rewards over other reinforcing rewards such as playing video games.
After identifying a group of characteristics shared by overweight people, Kessler and his fellow researchers looked for a study that collected data about attitudes, behavior, and weight. They found it in the Reno Diet Heart Study, a five-year mission to explore the connections between weight and cardiovascular health. Three years later, the next generation of the study gathered additional information:
Their data included true-or-false responses to statements such as "sometimes when I start eating, I just can't seem to stop," "my stomach often seems like a bottomless pit," and "I am always hungry so it is hard for me to stop eating before I finish the food on my plate." We also had answers to questions such as "How often are you preoccupied with thinking about food?"
Together, the information allowed us to focus on three behaviors of interest--loss of control over eating; lack of feeling satisfied by food; and preoccupation with food. Based on what I knew about the classic symptoms of other conditioned and driven behaviors, all three characteristics could reasonably be considered expressions of conditioned hypereating.
Kessler and his team discovered that 50 percent of obese subjects, 30 percent of overweight participants, and 17 percent of normal-weight participants shared multiple characteristics of the syndrome he calls conditioned overeating. He finds the 17 percent "sizable minority" worthy of a closer examination, and surmises that these thin people may be at risk for becoming overweight and obese. However, Kessler does not call attention to the even-more-sizable majority of overweight and obese who DON'T demonstrate the features of conditioned hypereating! He does, however, note that of the 50 percent of obese people who exhibit the symptoms, a good many more women than men are likely to do so (56 percent versus 43 percent). He also notes:
Those with evidence of conditioned hypereating were almost twice as likely to have been overweight early in life.
The grouping of survey answers allowed Kessler to identify more people exhibiting conditioned overeating. He then worked with another researcher to learn more about this subgroup, asking questions that were not asked during the Reno Diet Heart Study. In particular, Kessler and his colleague studied what happened when "conditioned overeaters" smelled chocolate, then tasted a chocolate milkshake:
Normally, a pleasing aroma becomes less pleasant over time as we habituate to it. Not so with conditioned hypereaters. People who scored higher on the scale of conditioned hypereating reported that the odor became more pleasant over time.
Then we looked at what was happening in people's brains...High-scoring individuals exhibited an enhanced level of neural activity as they responded to the cue of a chocolate odor...[followed by] the taste of a milkshake...
Especially interesting was the response in the amygdala. This area of the brain, which normally allows us to anticipate reward, was also activated among conditioned hypereaters while they were eating. "The heightened amygdala response drives the whole circuit out of whack," said Small. This suggests that the act of eating, when we might expect cue-induced anticipation to lessen, instead stimulates this vulnerable population.
Previous chapters from The End of Overeating:
Part 3: Conditioned Hypereating Emerges
Chapter 29 (part 2 - emotional eating) (reviewed by me)
Chapter 30: How We Become Trapped (reviewed by Clio2)
Chapter 29 (part 1): Why We Don't Just Say No (reviewed by me)
Chapter 28: What Weight-Loss Drugs Can Teach Us (reviewed by Clio2)
Chapter 27: Overeating Becomes More Dangerous (reviewed by me)
Part 2: The Food Industry
Chapter 26: Purple Cows (reviewed by Clio2)
Chapter 25: The Science of Selling (reviewed by me)
(there are links to Chapters 14 through 24 in my Chapter 25 review)
Part 1: Sugar, Fat, and Salt
Chapter 13: Eating Behavior Becomes a Habit (reviewed by me)
(there are links to Chapters 1 through 12 in my Chapter 13 review)
Scheduled WHEE diaries:
December 13
Sun AM - ???
Sun PM - Holiday Fit Club - kismet
December 14
Monday AM - NC Dem
Monday PM - ???
December 15
Tues AM - ???
Tues PM - Clio2 (Kessler, Ch. 32)
December 16
Weds AM - ???
Weds PM - Edward Spurlock
December 17
Thurs AM - ???
Thurs PM - ???
December 18
Fri AM - ???
Fri PM - ???
December 19
Sat AM - ???
Sat PM - Edward Spurlock (Kessler, Ch. 33)