How Emotions Affect Eating: a Five-Way Model
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ARTICLE IN PRESS Appetite 50 (2008) 1–11 www.elsevier.com/locate/appet Research Review How emotions affect eating: A five-way model Michael Macht Department of Psychology, University of Wu¨rzburg, Marcusstr. 9-11, 97070 Wu¨rzburg, Germany Received 18 April 2006; received in revised form 13 July 2007; accepted 16 July 2007 Abstract Despite the importance of affective processes in eating behaviour, it remains difficult to predict how emotions affect eating. Emphasizing individual differences, previous research did not pay full attention to the twofold variability of emotion-induced changes of eating (variability across both individuals and emotions). By contrast, the present paper takes into account both individual characteristics and emotion features, and specifies five classes of emotion-induced changes of eating: (1) emotional control of food choice, (2) emotional suppression of food intake, (3) impairment of cognitive eating controls, (4) eating to regulate emotions, and (5) emotion- congruent modulation of eating. These classes are distinguished by antecedent conditions, eating responses and mediating mechanisms. They point to basic functional principles underlying the relations between emotions and biologically based motives: interference, concomitance and regulation. Thus, emotion-induced changes of eating can be a result of interference of eating by emotions, a by- product of emotions, and a consequence of regulatory processes (i.e., emotions may regulate eating, and eating may regulate emotions). r 2007 Elsevier Ltd. All rights reserved. Keywords: Emotion; Eating; Mood; Emotional eating; Restrained eating; Motivation; Food choice Contents Introduction . 1 Variability of emotion-induced changes of eating . 2 Variability across individuals . 2 Variability across emotions . 3 Previous theories . 4 A five-way model . 4 Food-induced emotions control food choice . 5 Intense emotions suppress food intake . 5 Negative and positive emotions impair cognitive eating controls . 6 Negative emotions elicit eating to regulate emotions. 6 Emotions modulate eating in congruence with emotion features . 7 Discussion . 7 Emotion-induced eating in restrained and emotional eaters. 7 Emotion-induced eating in normal eaters . 8 References . 8 Introduction Emotions serve distinct motivational functions and E-mail address: [email protected] contribute essentially to control of basic behavioural 0195-6663/$ - see front matter r 2007 Elsevier Ltd. All rights reserved. doi:10.1016/j.appet.2007.07.002 ARTICLE IN PRESS 2 M. Macht / Appetite 50 (2008) 1–11 systems in animals and men (e.g. Frederickson, 1998; bility of emotion-induced changes of eating is summarized Frijda, 1986; Izard & Ackerman, 2000; Plutchik, 1984; briefly. Tomkins, 1963). Specific emotions such as anger, fear, sadness, and joy, as well as moods that are thought to last Variability of emotion-induced changes of eating longer and be more diffuse (e.g. Ekman, 1992; Frijda, 1993) have been found to affect eating responses along the entire Variability across individuals process of ingestion: motivation to eat (Macht & Simons, 2000), affective responses to foods (Ferber & Cabanac, A series of experiments showed that restrained eaters (as 1987; Willner & Healy, 1994), food choice (e.g. Gibson, identified by questionnaire; e.g. Herman & Mack, 1975; 2006; Oliver & Wardle, 1999), chewing (Macht, 1998), Stunkard & Messick, 1985) consume more food than non- eating speed (Krebs, Macht, Weyers, Weijers, & Janke, restrained eaters in response to fear and negative mood 1996), amount ingested (Greeno & Wing, 1994 for a states (for a review, see Greeno & Wing, 1994, also review), as well as metabolism and digestion (Blair, Wing, Heatherton, Striepe, & Wittenberg, 1998; Rotenberg & & Wald, 1991; Wing, Blair, Epstein, & McDermott, 1990). Flood, 1999; Rutledge & Linden, 1998; Tuschen, Florin, & Surveys demonstrate that most people experience changes Baucke, 1993). Restrained eating refers to a persistent of eating in response to emotional stress (on average 30% pattern of eating-related cognitions and behaviours in an increase and 48% a decrease of appetite or intake, order to reduce or to maintain body weight (Herman & Table 1). Epidemiological data indicate that stress-related Mack, 1975). Another experiment demonstrated that eating is associated with increased body weight (Laitinen, emotional eaters (also identified by questionnaire; van Ek, & Sovio, 2002). Not surprisingly, effects of emotions Strien, Frijters, Bergers, & Defares, 1986) consume more on eating have been studied extensively, but due to their sweet, high-fat foods in response to emotional stress than variability it remains difficult to predict how an emotion non-emotional eaters (Oliver, Wardle & Gibson, 2000). affects eating in a given group of persons. Field studies showed that negative emotional states in Emotions can increase food intake in one group of everyday life can be associated with a tendency to eat as an persons, e.g. restrained eaters, but decrease food intake in emotion regulation strategy (Macht, Haupt, & Ellgring, another group, e.g. non-restrained eaters. Furthermore, 2005; Macht & Simons, 2000). Emotional eating is thought different emotions may increase or decrease eating in the to be instigated in order to cope with negative emotions same group of individuals. For example, boredom may be (Bruch, 1973; Kaplan & Kaplan, 1957). associated with increased appetite, but sadness with Probably, the influences of both eating habits are decreased appetite (e.g. Pudel & Richter, 1980). This reflected in effects of emotions on binge eating. Negative twofold variability (across individuals and emotions) has emotions have been found to increase the tendency to binge been neglected by previous research. Based on an in bulimia nervosa and the binge eating disorder (experi- individual difference model, it was mostly examined ments: Agras & Telch, 1998; Cattanach, Malley, & Rodin, whether eating habits predispose people to increase food 1988; Chua, Touyz, & Hill, 2004; Gluck, Geliebter, Hung, intake in response to negative emotions (Greeno & Wing, & Yahav, 2004; Telch & Agras, 1996; field studies: Alpers 1994). The present paper introduces an integrative model & Tuschen-Caffier, 2001; Cooper & Bowskill, 1986; Davis, that takes into account both individual characteristics and Freeman, & Garner, 1988; Johnson & Larson, 1982; emotion features. First, the empirical evidence on varia- Kenardy, Arnow, & Agras, 1996). Taken together, studies indicate that restrained eaters increase food intake, emotional eaters consume more sweet, high-fat foods, Table 1 and binge eaters tend to binge in response to negative Changes of eating in response to emotional stress reported in surveys emotions. Change of eating N Reference By contrast, normal eaters (i.e. normal-weight persons whose emotional and restrained eating scores fall within 11% more appetite, 70% 364 Krumbacher and Meyer the normal range) are usually assumed to reduce food less appetite (1963) intake in response to negative emotions (Herman & Polivy, 16% more appetite, 38% 1950 Pudel and Richter (1980) less appetite 1984; Schachter, Goldman, & Gordon, 1968). The evidence 25% more appetite, 32% 1024 Pudel (1984) does not support this assumption. Table 2 summarizes less appetite experimental studies in normal-eating populations: 43% of 44% eat more, 48% eat 80 Willenbring et al. (1986) the results indicate an increase, 39% a decrease and 26% less no change of eating in response to emotions (as shown by 4% eat more, 55% eat less 475 Popper et al. (1989) 49% eat more, 51 do not 500 Spillman (1990) Bellisle et al. (1990), in the latter studies possibly one part eat more of the sample reduced and the other part increased food 55% eat more, 45% do 101 Weinstein et al. (1997) intake). not eat more Similarly, surveys and field studies showed that stress 38% eat more, 42% eat 212 Oliver and Wardle (1999) and negative emotions can be associated with both less increased and decreased motivation to eat and food intake ARTICLE IN PRESS M. Macht / Appetite 50 (2008) 1–11 3 Table 2 Effects of emotions on eating: experimental studies in normal subjects Effect Eating measure Emotion Reference Increase Food intake Negative mood Lowe and Maycock (1988) Negative mood Willner et al. (1998) Fear Pine (1985) Fear Pines and Gal (1977) Fear Bellisle et al. (1990) Arousal Glass (1967) Arousal Cantor et al. (1982) Arousal Grunberg and Straub (1992) Boredom Abramson and Stinson (1977) Anger Macht (1996) Hedonic responses Arousal/stress Ferber and Cabanac (1987) Joy Macht et al. (2002) Motivation to eat Joy Macht et al. (2002) Anger Macht (1996) Chocolate craving Negative mood Willner et al. (1998) Decrease Food intake Negative mood Baucom and Aiken (1981) Fear Schachter et al. (1968) Fear Herman and Polivy (1975) Fear Heatherton et al. (1991) Fear Herman et al. (1987) Fear Bellisle et al. (1990) Arousal Grunberg and Straub (1992) Hedonic responses Depressive mood Willner and Healy (1994) Sadness Macht et al. (2002) Motivation to eat Sadness Macht et al. (2002) Arousal Macht (1998) Chewing Arousal Macht (1998) Effect Eating measure Emotion Reference No effect Food intake Negative mood Frost et al. (1982) Negative mood Tuschen et al. (1993) Negative mood Telch and Agras (1996) Negative mood Ruderman (1985) Fear Reznick and Balch (1977) Fear Heatherton et al. (1991) Fear Schotte et al. (1990) Fear Cools et al. (1992) (Table 1; de Castro, 1986; Hill, Weaver, & Blundell, 1991; Animal studies point to a role