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Both naturalistic and laboratory-based studies contribute to the understanding of human eating behavior
Appetite,
1992, 19, 76-77
Commentary Both Naturalistic and Laboratory-Based Studies Contribute to the Understanding of Human Eating Behavior BARBARA J. ROLLS and DAVID J. SHIDE Department of Psychiatry & Behavioral Sciences, Johns Hopkins University School of Medicine
In stating that there is a need for more naturalistic studies of human eating behavior Meiselman (1992) is preaching to the converted. We have made a number of statements with the same message: “In most studies of diet and behavior there is a trade-off between rigorous control and naturalistic situations. The design that is chosen should be determined by the question being asked. Ideally, a number of approaches should be tried with the hope that the laboratory-based and naturalistic studies will ultimately lead to similar conclusions” (Rolls & Hetherington, 1990).
Similarly, in a recent review of effects of intense sweeteners, the following conclusion was reached: “Little information is available on how the use of intense sweeteners affects food-consumption patterns and body weight in community-dwelling individuals. More long-term naturalistic studies are needed, but these are intrinsically difficult because of problems with measuring intake and ensuring compliance to dietary regimens. Because it is difficult to know whether rigorous laboratory-based studies can be extrapolated to natural situations and because field studies lack precision, parallel studies should be run in the laboratory and the field to determine whether they lead to similar conclusions about the effects of sweeteners on food intake and body weight” (Rolls, 1991). Clearly, we need both lab studies and field studies, and both types have advantages and disadvantages. The bottom line though is that we choose a method that best suits the question being asked. Meiselman says that he is interested in what controls when we eat, what we eat, and why we eat. He is interested in “real life”, and suggests that studies conducted in institutions such as prisons or hospitals are a way of getting at this. If the argument is one of context, the question arises as to how general&able are results generated in such settings? Is a prison or hospital setting the single most appropriate place to study the rich interplay of contextual and sociocultural influences on human eating behavior? This begs the larger question of “what is normal eating behavior”? Is the evening meal at home, prepared in the kitchen from the vast array of foods available at the local supermarket, normal? Is lunch at work, eaten at a cafeteria or on the run, normal, or is normal a synthesis or summation of diverse and complex daily meal patterns, as they relate to longer-term Address correspondence to Barbara J. Rolls, Program in biobehavioral University, 104 Benedict House, University Park, PA 16802, U.S.A. 0195-6663/92/040076+02
$08.00/O
0
health, Pennsylvania
1992 Academic
State
Press Limited
NATURALISTIC AND LABORATORY-BASED STUDIES
77
patterns of caloric intake and body-weight regulation? If you find differences between various meals and their settings, which meal represents “real life”? “Normal” eating behavior may be quite different in each of the settings we choose to study it in. If we are interested in ordinary people eating in natural environments, clearly field work is appropriate. We disagree with the notion that there is not a lot of this type of work being done. Much of it is done by nutritionists, dietitians, anthropologists, etc. A problem with naturalistic studies is that most of the methods available are either not very precise, do not lend themselves to manipulation, or are very expensive. Also, it can be argued that field studies can never really be designed to give a comprehensive view of the influences on food intake. “Since eating behavior is so complex, one could argue that the best way to understand factors which influence food intake and selection is to study an entire community over a number of years recording cultural, environmental, economic and developmental influences, in addition to observing each individual’s selection of food, duration of eating, rate of consumption, amount of food eaten and frequency of meals” (Hetherington & Rolls, 1987). Whether we are working in the field or in the lab, our studies of human eating must focus on clearly defined questions or problems. Also, we must bear in mind that funding agencies insist that our studies be hypothesis-driven. Perhaps Meiselman will be able to convince us otherwise, but it seems that hypothesis-driven studies can be more readily conducted in a controlled lab setting than in the field. Finally, many of the scientists who traditionally publish in Appetite are interested in the physiological mechanisms regulating food and fluid intake. A controlled laboratory setting is most appropriate for this type of investigation, which is likely to involve the precise manipulation or measurement of defined variables. These studies in no way preclude or pre-empt naturalistic studies. They can, however, lead to an understanding of general principles underlying food intake which can be used to design studies in the field. Observational studies also frequently form the background for designing controlled lab studies. Arguing across different levels of analysis over what is the appropriate or ideal way to study human eating behavior is fruitless as there is no single correct way to address the issue. The most satisfactory explanation will come from combining as many levels of analysis as possible in a model that takes into account physiological, psychological, and sociocultural influences in a synthetic fashion. We need an integrative approach to the study of human food intake which combines the best of lab and field studies; debates over which type of investigation is best or needed most will not serve this end.
Hetherington, M. & Rolls, B. J. (1987) Methods of investigating human eating behavior. In F. Toates & N. Rowland (Ed& Feeding and Drinking Pp. 77-109. Elsevier: Amsterdam. Meiselman, H. L. (1992) Methodology and theory in human eating research. Appetite, 19, 49-55. Rolls, B. J. (1991). Effects of intense sweeteners on hunger, food intake, and body weight: a review. American Journal of Clinical Nutrition, 64, 872-878. Rolls, B. J. & Hetherington, M. (1990) A behavioral scientist’s perspectives on the study of diet and behavior. In G. H. Anderson (Ed.), Diet and Behavior Pp. 209-219. Springer Verlag: London.
1992, 19, 76-77
Commentary Both Naturalistic and Laboratory-Based Studies Contribute to the Understanding of Human Eating Behavior BARBARA J. ROLLS and DAVID J. SHIDE Department of Psychiatry & Behavioral Sciences, Johns Hopkins University School of Medicine
In stating that there is a need for more naturalistic studies of human eating behavior Meiselman (1992) is preaching to the converted. We have made a number of statements with the same message: “In most studies of diet and behavior there is a trade-off between rigorous control and naturalistic situations. The design that is chosen should be determined by the question being asked. Ideally, a number of approaches should be tried with the hope that the laboratory-based and naturalistic studies will ultimately lead to similar conclusions” (Rolls & Hetherington, 1990).
Similarly, in a recent review of effects of intense sweeteners, the following conclusion was reached: “Little information is available on how the use of intense sweeteners affects food-consumption patterns and body weight in community-dwelling individuals. More long-term naturalistic studies are needed, but these are intrinsically difficult because of problems with measuring intake and ensuring compliance to dietary regimens. Because it is difficult to know whether rigorous laboratory-based studies can be extrapolated to natural situations and because field studies lack precision, parallel studies should be run in the laboratory and the field to determine whether they lead to similar conclusions about the effects of sweeteners on food intake and body weight” (Rolls, 1991). Clearly, we need both lab studies and field studies, and both types have advantages and disadvantages. The bottom line though is that we choose a method that best suits the question being asked. Meiselman says that he is interested in what controls when we eat, what we eat, and why we eat. He is interested in “real life”, and suggests that studies conducted in institutions such as prisons or hospitals are a way of getting at this. If the argument is one of context, the question arises as to how general&able are results generated in such settings? Is a prison or hospital setting the single most appropriate place to study the rich interplay of contextual and sociocultural influences on human eating behavior? This begs the larger question of “what is normal eating behavior”? Is the evening meal at home, prepared in the kitchen from the vast array of foods available at the local supermarket, normal? Is lunch at work, eaten at a cafeteria or on the run, normal, or is normal a synthesis or summation of diverse and complex daily meal patterns, as they relate to longer-term Address correspondence to Barbara J. Rolls, Program in biobehavioral University, 104 Benedict House, University Park, PA 16802, U.S.A. 0195-6663/92/040076+02
$08.00/O
0
health, Pennsylvania
1992 Academic
State
Press Limited
NATURALISTIC AND LABORATORY-BASED STUDIES
77
patterns of caloric intake and body-weight regulation? If you find differences between various meals and their settings, which meal represents “real life”? “Normal” eating behavior may be quite different in each of the settings we choose to study it in. If we are interested in ordinary people eating in natural environments, clearly field work is appropriate. We disagree with the notion that there is not a lot of this type of work being done. Much of it is done by nutritionists, dietitians, anthropologists, etc. A problem with naturalistic studies is that most of the methods available are either not very precise, do not lend themselves to manipulation, or are very expensive. Also, it can be argued that field studies can never really be designed to give a comprehensive view of the influences on food intake. “Since eating behavior is so complex, one could argue that the best way to understand factors which influence food intake and selection is to study an entire community over a number of years recording cultural, environmental, economic and developmental influences, in addition to observing each individual’s selection of food, duration of eating, rate of consumption, amount of food eaten and frequency of meals” (Hetherington & Rolls, 1987). Whether we are working in the field or in the lab, our studies of human eating must focus on clearly defined questions or problems. Also, we must bear in mind that funding agencies insist that our studies be hypothesis-driven. Perhaps Meiselman will be able to convince us otherwise, but it seems that hypothesis-driven studies can be more readily conducted in a controlled lab setting than in the field. Finally, many of the scientists who traditionally publish in Appetite are interested in the physiological mechanisms regulating food and fluid intake. A controlled laboratory setting is most appropriate for this type of investigation, which is likely to involve the precise manipulation or measurement of defined variables. These studies in no way preclude or pre-empt naturalistic studies. They can, however, lead to an understanding of general principles underlying food intake which can be used to design studies in the field. Observational studies also frequently form the background for designing controlled lab studies. Arguing across different levels of analysis over what is the appropriate or ideal way to study human eating behavior is fruitless as there is no single correct way to address the issue. The most satisfactory explanation will come from combining as many levels of analysis as possible in a model that takes into account physiological, psychological, and sociocultural influences in a synthetic fashion. We need an integrative approach to the study of human food intake which combines the best of lab and field studies; debates over which type of investigation is best or needed most will not serve this end.
Hetherington, M. & Rolls, B. J. (1987) Methods of investigating human eating behavior. In F. Toates & N. Rowland (Ed& Feeding and Drinking Pp. 77-109. Elsevier: Amsterdam. Meiselman, H. L. (1992) Methodology and theory in human eating research. Appetite, 19, 49-55. Rolls, B. J. (1991). Effects of intense sweeteners on hunger, food intake, and body weight: a review. American Journal of Clinical Nutrition, 64, 872-878. Rolls, B. J. & Hetherington, M. (1990) A behavioral scientist’s perspectives on the study of diet and behavior. In G. H. Anderson (Ed.), Diet and Behavior Pp. 209-219. Springer Verlag: London.