My colleagues Sara Dow, Morris Moscovitch, and Suparna Rajaram and
I recently demonstrated the importance of this practice. We offered a
full lunch to two severely amnesic people, who have no memory of having
just eaten. After they completed lunch we removed the tray, and 10 or so
minutes later announced that lunch had arrived (a meal identical to the
first). On three occasions, the amnesiacs readily downed the second
serving. And both started to eat eagerly again when we brought a third
meal more than 10 minutes after they finished the second. When we tried
this with people with a normal memory, they looked at us as if we were
crazy when the second meal arrived, and said something like, "I just
ate." (Note: They didn't say they weren't hungry!).
There are other nonphysiological factors determining how much we
eat. These include the social context of eating, our beliefs about eating
and health, whether we are dieting, and so on. The point is that we can
spend another 30 years measuring blood glucose at the onset and
termination of meals, but we will find out only a small part of what
determines the size of a human meal. Indeed, several important metabolic
factors influence our eating, but they only modulate our meal size and
seem to work in a subtle way from meal to meal, day to day, and week to
week.
When it comes to why we eat what we do -- namely, food choice -- the
situation is different. There has been very little work done on this
problem, perhaps a few percent of all of the studies on eating. It seems
obvious that culture is a major determinant of what we eat; does anyone
doubt that a Chinese person raised in an American household will have
American food habits?
Furthermore, there is not a simple "coin of the realm" for food
choice. Calories fill the bill for food intake. But for food choice,
there are also macronutrients (carbohydrates, fat and proteins) and a
variety of minerals and vitamins, all of which have to be consumed in
minimal amounts. The complexity of food choice and the clear involvement
of culture probably put psychologists off. But we cannot continue to
ignore the study of why we eat what we do. Food is a major part of our
life, a great source of pleasure, and in the U.S. in recent decades, a
major source of worry and stress.
There is no doubt that our culture has shaped how we view food. For
Americans and many others in the industrialized world, food intake has
undergone a major change during this century, giving rise to the
"American dilemma." There are at least five aspects of this
change.
First, there is the epidemiological revolution. At the beginning of
the century, life expectancy was about half of what it is now, and most
deaths resulted from infectious diseases such as cholera, malaria,
influenza and the like. With the conquest of most of these diseases in
the industrialized world, along with public health measures, the major
health threats today are degenerative diseases such as coronary heart
disease, cancer, stroke and Alzheimer's disease. In the era of infectious
diseases, the delay between behaviors and illness was generally short.
But the behaviors related to degenerative diseases are often separated by
decades, making the consequences of our actions seem too distant to pose
a salient threat in the here and now.
Second, there is an excess of food. We were built to eat food when
it became available. We are now faced with a surfeit, in both amount and
variety, though we still don't embrace variety as the French do.
Third, there is the reduction in activity. Modern technology has
reduced the amount of physical effort that most people need to earn a
living. Of course, it's also provided a wide variety of labor-saving
devices, as well as forms of entertainment that require no physical
effort. So we're eating more and moving less -- a sure recipe for weight
gain.
Fourth, while there is an abundance of risk information linking
food and other habits to long-delayed positive or negative health
consequences, these relationships are often very small. They would never
be discoverable within an individual lifetime, so they become
irrelevant.
Fifth, we are not educated to understand risks, benefits, nutrition
or the nature of science, all of which are critical for acting prudently
in the face of all the risk information we are exposed to. For example,
colleagues and I have discovered that a substantial minority of Americans
think of fat and salt as toxins, such that any amount of these necessary
nutrients is considered unhealthful. But, of course, that is
untrue.
With the great publicity for diet-health links, and a great desire,
especially among women, to be thin, eating has become an ambivalent act.
True, it is necessary for life. True, it is often a source of great
pleasure. But, especially in America, it is also viewed as unhealthful,
in many ways. Almost everyone believes that not eating is riskier than
eating; but eating the "right" things and staying off the usually highly
palatable "wrong" things has become a daily stress in life.
Many have pointed to the prevalence of eating disorders, the fact
that obesity is actually increasing in the United States, and the fact
that our stores are simultaneously filled with "low cal" and "low fat"
foods, adjacent to tempting high-calorie, high-fat foods. The American
supermarket's yogurt section (unlike that of the French) is populated
almost entirely by low- or nonfat yogurt. But have a look at our
bakeries. The ambivalence is present in the store itself.
Tags:
american dilemma,
apparent conflict,
cardiovascular disease in france,
care quality,
conservation of energy,
culture,
culture and health,
determinants of health,
diet,
eating,
eating culture,
excess calories,
fewer calories,
french diet,
french paradox,
healthful diets,
medical establishment,
paul rozin,
physical health,
principal cause,
sizable segment,
swedes,
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