December 7, 1996
In the throes of this holiday season, goodies of every type beckon. There are the lavish family dinners, the office parties, the open-house buffets, the basket of sweets lovingly prepared by a neighbor -- and that seemingly never-ending supply of rich leftovers.
If ever there were a time when we were tempted to chronically overeat, this is it. Despite warnings about the risks involved, who can resist the creamy eggnog, spiked apple cider, Hanukkah-gelt chocolates, or buttery Christmas cookies?
So we overeat. And then diet -- usually unsuccessfully.
One new study suggests that men and women tend to overeat for different reasons -- and in different ways. A second, and perhaps more worrisome, survey confirms what every chronic dieter understands all too well: that knowing what we shouldn't eat is a poor deterrent.
In the first study, psychologists from Duke University and Structure House, a Durham, N.C., weight-control institute, teamed up to probe what motivates overweight people to overeat. They interviewed 329 men and 855 women from around the country who had enrolled at the institute between 1990 and 1995 for therapy aimed at behavior modification.
These people do not represent a cross section of the U.S. population. All were morbidly obese, points out Duke's Philip R. Costanzo. Some women tipped the scale at 300 pounds, a few men approached 400. But they reached their immense proportions by doing what so many of us do: chronically overeating -- nibbling or even gobbling when not really hungry, often in response to social or emotional cues.
Many previous studies have indicated that persons who are heavy frequently suffer from depression. And indeed, some 30 percent of the women and 20 percent of the men at the time of the interview were moderately to severely depressed. That's a rate five times what's seen in the U.S. population generally, Costanzo observes. Moreover, at least 65 percent of the studied men and women reported a history of depression.
Their depression often appeared to stem at least in part from the individuals' "failure at gender roles as the larger society defines them," Costanzo says. For women, this might be not fitting the svelte image that commercial society has promulgated. For men, it might involve a failure to measure up to a macho, tough-guy role.
Feelings of depression can powerfully affect eating behavior. The new study found that both the men and women reported being more likely to overeat when they were experiencing negative emotions.
Eating behavior in reaction to such negative feelings, however, proved a big surprise. Costanzo puts it simply: "We find in this study that men who are depressed and overweight are different animals than women who are depressed and overweight."
The women tended to overeat when they were sad or angry -- especially when "they were ticked," he notes. They also proved likely to binge, that is, to eat large quantities of food at a single sitting. Moreover, as in a number of previous studies by others, these women tend to eat in isolation. Depressed, obese women "eat a hell of a lot more when they're alone than when they're not alone," Costanzo told Science News Online.
Men, in contrast, proved more likely to eat because "they were simply lonely." In general, such men tended to be "very passive, very compliant -- easily stimulated to eat by those around them." So when Aunt Sarah suggests that they take another helping of potatoes, or another slice of pie, Costanzo says, they do. At a business lunch, when everybody else is ordering an appetizer, they will also -- in an effort to fit in. Finally, these men "are not bingers," Costanzo observes.
While their behaviors are notably different, heavyset depressed men and women both are likely to find the celebratory season particularly troublesome. Not only do holidays breed depression in susceptible individuals, but there is also an ample supply of food and plenty of encouragement to devour it.
Costanzo believes that helping such individuals successfully weather food-rich occasions requires more than telling them to diet. The new study "is pointing toward a need to repair some of the emotional damage that stems from a lifelong struggle with rejection," he says, because the "emotional damage continues to drive a kind of deviant behavior that leads individuals to maintain their obesity." In many cases, he's found, the feelings of rejection that these people are responding to began long before the obesity set in.
Nor are obese people the only ones who suffer. Anorexics, who diet compulsively all the time, and bulimics, who binge and then vomit, suffer from many of the same underlying problems, Costanzo says. The only difference between them and the obese, he says, is that they successfully keep down their weight through their maladaptive behaviors.
Once these heavyweights trim down, then what? That's the big, unanswered question, Costanzo notes, "because virtually anybody can lose weight." The problem comes in keeping it off. And that requires "maintaining a lifestyle that doesn't force you to diet for the rest of your life."
A new study by researchers at the Fred Hutchinson Cancer Research Center in Seattle suggests the answer is not as simple as educating people about what foods are healthy.
In a study they published in the October American Journal of Public Health, these scientists reported data from a survey of 600 residents randomly selected from throughout Washington State. They administered a first questionnaire in 1989, when much of the public was still eating high fat diets. It not only asked people what they ate but also assessed their knowledge about diet -- such as whether particular foods were high or low in fat and what they knew about diet's link to heart disease and cancer. Then the researchers administered a similar questionnaire 3 years later to observe how, if at all, the subjects' own diet had changed over that time.
The big surprise, says nutritional epidemiologist Ruth E. Patterson, who led the study, was "how well people did on their knowledge of food composition -- and how unimportant this was in predicting whether they would adopt a healthful diet." Pressure from friends and family about the need to adopt a healthier diet also proved a useless motivator. About the only surveyed factor that predicted a healthy change in eating habits was a strong, personal belief that eating better would help prevent disease.
"Sometimes we [in the public health field] approach people like we're their nannies or mothers, telling them to eat more vegetables or less fried foods," Patterson observes. This study suggests such shoulds and shouldn'ts fall on deaf ears.
"We really aren't sure what components of public health education work. So we just make up brochures and pass out all this information -- hoping and praying it makes a difference." On the basis of her data, Patterson now suspects the health community would be more persuasive if it sought to compel changes through education that focused on the science, explaining the evidence behind those dietary dos and don'ts.
But even healthful changes may not by themselves result in weight loss. In fact, the researchers found that the more educated adults in their sample tended to lower their fat intake during the 3 years between the questionnaires-- "while gaining more weight than less educated adults." Though she doesn't have any data to resolve this paradox, Patterson suspects that the better educated group adopted a more sedentary lifestyle.
References:
Kristal, A., R. Patterson, et al. 1995. Psychosocial correlates of healthful diets and intention to improve diet: Baseline results from the Working Well study. Preventive Medicine 24:221.
Musante, G.J., P.R. Costanzo, and K.E. Friedman. In press. The comorbidity of depression and eating disregulation processes in a diet-seeking obese population: A matter of gender specificity. International Journal of Eating Disorders.
Patterson, R.E., A.R. Kristal, and E. White. 1996. Do beliefs, knowledge, and perceived norms about diet and cancer predict dietary change? American Journal of Public Health 86(October):1394.
Sources:
Philip R. Costanzo
Department of Psychology
Duke University
Durham, NC 27708
Ruth E. Patterson
Cancer Prevention Program
Fred Hutchinson Cancer Research Center
1124 Columbia
MP 702
Seattle, WA 98104
This week's Food for Thought is prepared by Janet Raloff, senior editor of Science News.
Illustration: Wendy Temple.
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