Five Reasons to Distrust the Trust Model
Article first published online: 6 SEP 2012
2009 North American Association for the Study of Obesity (NAASO)
Volume 17, Issue 6, pages 1107–1111, June 2009
How to Cite
Kirschenbaum, D. S. and Kelly, K. P. (2009), Five Reasons to Distrust the Trust Model. Obesity, 17: 1107–1111. doi: 10.1038/oby.2009.68
- Issue published online: 6 SEP 2012
- Article first published online: 6 SEP 2012
- Received 12 November 2008; accepted 2 February 2008
Eneli et al.'s (1) recent Comment in Obesity ostensibly made “a strong case for conducting research comparing the trust model to more traditional dietary approaches for treating childhood obesity” (p. 2202). The trust model cogently emphasizes the critical role parents play in the development and treatment of obesity (2,3). It also stresses the value of empowering children as much as possible to regulate their own efforts to change their lives. Both of these points are embraced and incorporated in most current scientifically based treatments for childhood obesity (4,5,6); however, the scientific evidence does not support most of the model's assertions or indicate that the trust model is a viable alternative to extant conceptualizations and interventions. This comment describes the evidence that reveals five flaws in the trust model's beliefs and recommendations.
The trust model: beliefs and recommendations
Table 1 summarizes the trust model's beliefs and recommendations to parents. This summary is based on Satter's original 1986 formulation (2), her 1996 paper (7), her 2005 self-help book (3), and Eneli et al.'s review and analysis (1). As shown in Table 1, the trust model clearly emphasizes the key roles parents can play and the value of helping children take responsibility for their own eating (“primary behavioral recommendations” 1–6). This approach makes a great deal of sense, is certainly valued in cognitive-behavioral treatments for pediatric obesity, and has empirical support (e.g., benefits of increasing family mealtimes (8)). However, as the following presentation of five flaws show, the model's core beliefs, and the behavioral recommendations derived from it are, for the most part, not supported by the scientific evidence.
Flaw 1: Rigorous efforts by overweight children at weight control within professionally conducted treatment programs WILL backfire (i.e., cause disordered eating, accelerated weight gain, and negative emotional reactions); in the long run such treatments are INEFFECTIVE.
Evidence indicates: Rigorous efforts by overweight children at weight control within professionally conducted treatment programs will NOT backfire (i.e., cause disordered eating, accelerated weight gain, and negative emotional reactions); in the long run such treatments are EFFECTIVE for many participants.
Eneli et al. stated (1; p. 2197), “dietary restriction has been shown to backfire, as it is associated with preoccupation with food, eating in the absence of hunger, poorer self-esteem, and further weight gain.” This quote echoes Satter's opinion, “[W]eight control programs are highly likely to destabilize normal growth processes and, in the long run, make children fatter rather than thinner” (7; p. 860). These statements imply that current treatments of childhood obesity, which focus on dietary restriction (e.g., “small portion sizes, fat restriction, and calorie awareness pursued rigorously [in] current dietary treatments” (1; p. 2197)) cause these adverse backfiring effects far more often than producing sustained weight loss (“The efficacy of current dietary treatments, particularly for long-term weight maintenance is doubtful” (1; p. 2197)).
Eneli et al. cited four studies (9,10,11,12) to support this backfiring notion, most of which Satter cited in a related vein, as well (3). None of these studies attempted to test any type of treatment program (let alone a rigorous one) for overweight children; however, all were correlational studies that provided minimal bases for drawing conclusions about the effects of pursuing dietary restrictions rigorously in the context of professionally delivered treatment.
Regarding the potential of rigorous treatments of obesity to cause, paradoxically, increases in degree of excess weight (the key element of the backfiring hypothesis), two of the four studies cited by Eneli et al. to support the backfiring assertion did not measure change in weight status at all (9,12). The other two studies found that overweight young people tended to report more frequent dieting than nonoverweight children and teenagers during their initial assessments (10,11). Dieting, assessed in various ways, did correlate with subsequent weight gains (e.g., increases in BMI) in these studies; however, these researchers inappropriately used analyses of covariance to attempt to eliminate the impact of initial weight status. It was inappropriate to attempt to covary out a factor that was very likely to impact the dependent measure (weight change), and deserved scrutiny as a potential confounding variable. It seems probable that initial degree of overweight predicted the weight gain in more significant ways than did dieting status per se (see, for example, Stice et al.'s reanalysis of the assessment of the onset of obesity 11; p. 972).
Numerous reviews and theoretical analyses show that obese individuals must battle strong biological tendencies toward weight gain (13,14,15). Deliberate conscious and consistent weight controlling behaviors (e.g., dieting behaviors) seem imperative in order to prevent gaining excess weight (16,17). Overweight young people tend to diet more and gain excess weight more commonly than their never-overweight peers. This does not show that dieting per se leads to gaining weight.
One error of omission in this regard is that Eneli et al. used a paper published in 1999 by Stice et al. to support their backfiring hypothesis, but they did not mention a paper published by Stice in 1998 (18) (which was discussed in Stice's 1999 paper). In the 1998 paper, Stice found that students who reported using a low-to-moderate number of dietary strategies (“low dieters” and “moderate dieters”) tended to gain weight (increase BMI) over time. The trust model asserts that this finding suggests that dieting can backfire or cause weight gain. Stice's (18) low-to-moderate dieters were apparently trying, perhaps sporadically, to lose weight with various strategies and were not successful. The trust model would clearly suggest that Stice's teenagers, who used especially rigorous deliberate efforts to lose weight (i.e., those whom he called “extreme dieters”), would be more likely than the low-to-moderate dieters to gain weight over time (the backfiring effect). The opposite occurred; therefore, Stice concluded, “[M]ild to moderate dietary efforts are not powerful enough to thwart biologically and behaviorally driven weight gain over time, but that more extreme levels of dietary efforts are successful at reducing weight” (18; p. 292).
More recently, Presnell and Stice (19) examined this backfiring hypothesis via a true experiment, not a correlational study. These researchers randomly assigned overweight women to either a 6-week low calorie diet or a waitlist control condition. They measured weight change, binge eating behaviors, and other bulimic symptoms. The backfiring hypothesis would suggest that the diet should have led to disordered eating and weight gain. Again, the opposite occurred. As in two prior studies similar to this one that were cited by Presnell and Stice, dieters lost weight and decreased binge eating when they were dieting and in the weeks subsequent to dieting.
Overweight status at any point in time is almost always a good predictor of deliberate attempts to lose weight and gain weight over time (13,20). For example, in a recent naturalistic study, Phelan et al. (21) showed that successful weight controllers exerted far more effort (used more deliberate “dieting” strategies like planning before going to parties) in order to maintain their weight during the holidays compared to nonweight controllers. Although the weight controllers had a long history of successful maintenance of reduced weight, they were still much more likely than nonweight controllers to gain ≥1 kg during the holidays. These findings could lead some observers to conclude that dieting among overweight people leads to weight gain. A more parsimonious explanation indicates, however, that the powerful antagonistic biological forces with which weight controllers must grapple every day can lead to weight gain when they face high-risk situations. Only when weight controllers adopt very consistent focusing and equally consistent dietary and activity behaviors, termed a healthy obsession by Kirschenbaum (22), can they master these biological challenges even during the holidays (18,23).
Boutelle et al. (24) demonstrated this point in an experiment. One group of active weight controllers who had been attending weekly cognitive-behavior therapy sessions for several months received an intervention during the holiday weeks (Thanksgiving–Christmas), designed to increase consistency of their self-monitoring (additional phone calls from their therapists; numerous mailings that reminded them of the value of self-monitoring). The comparison group merely received their usual weekly sessions. As expected, the comparison group decreased their consistency of self-monitoring and gained weight during the holiday weeks. The intervention group maintained their consistency in self-monitoring and lost weight, even during the high-risk holiday weeks. Phelan et al. (21) also found that generally successful weight controllers who self-monitored eating and weight relatively more consistently during the holidays maintained their weight more effectively than those whose self-monitoring decreased during the holidays, very much in accord with related findings from other studies of masterful weight controllers (25,26).
Eneli et al. also cited the restraint literature as supportive of the trust model's view that dieting causes disordered eating. The restraint literature includes many studies in laboratory settings that compared those who scored high on one of the “Restraint” scales (“restrained eaters” (23)) with low scorers on one of the restraint scales (“unrestrained eaters”). Restrained eaters report high levels of conscious efforts to control what and how much they eat, negative emotional reactions to deviations from their eating plans, and relatively frequent fluctuations in weight. The paradigm used to examine this construct has some participants consume a high-calorie milkshake (a “preload”) while others do not eat the preload; then, all subjects complete a taste test of various flavors of ice cream. Normal eaters were expected to regulate their consumption of food by eating less ice cream after a preload. In some studies, unrestrained eaters did regulate their eating that way (13,23); restrained eaters, however, often “counter-regulated” by eating more, not less, of the ice cream in the taste test after consuming the milkshake preload. This type of counter-regulatory eating was viewed as disordered or binge eating by the restraint researchers and by Satter (7) and Eneli et al. (1; p. 2199). Satter and Eneli et al. viewed restrained eaters as active dieters and used these findings to support the trust model's position—that dieting leads to disordered eating.
A substantial amount of research on restrained eaters has shown (since the early 1990s) that it is erroneous to assume that a high score on the Restraint scale accurately identifies active dieters (13,27). Restrained eaters may or may not be active dieters, as it turns out. Some restrained eaters—those who are not actively attempting to diet and lose weight—tend to counter-regulate or binge eat. In sharp contrast, those restrained eaters who are actively attempting to diet in order to lose weight do not counter-regulate in this laboratory paradigm. To the contrary, active dieters significantly reduce their consumption of ice cream after consuming the milkshake preload—exhibiting regulatory eating (13,27). These findings coincide with Stice's (18) observations about dieting patterns among high school students. Serious weight controllers (Stice's “extreme dieters” and restrained eaters who are actively dieting) can restrict calorie intake, maintain regulatory eating when challenged, and lose weight.
In accord with Stice's (18) conclusions, studies of successful weight controllers make it especially clear that more stringent weight controlling efforts generally produce the best outcomes. McGuire et al. (25) asked successful weight controllers to describe how they achieved their success. These masters of weight control had maintained substantial weight losses for an average of six years after having gained and lost 270 lbs before becoming successful. Sixty percent of these masters reported adopting more stringent standards of eating (with much less fat intake) and 80% reported significantly increasing their activity levels.
The assertion that rigorous weight control efforts by children can backfire to cause psychological distress (“lowered self-esteem”) is inconsistent with evidence to the contrary. Treatment programs for obese children routinely assess psychological impact and just as routinely find either no negative impact (17,28,29) or, more commonly, psychological benefits (30,31,32,33,34,35). For example, Walker et al. (34) focused on change in body image, self-esteem, and worries in obese adolescents in an immersion program. Even though these participants reported significantly lower self-esteem scores when initially compared to a control group, their self-esteem scores increased in direct proportion to decreases in excess weight and improvements in athletic skills.
The final point of the backfiring hypothesis concerns the outcomes of current treatment programs for childhood obesity. As will be discussed under Flaw 5 in more detail, despite the backfiring hypothesis and the doubts expressed in the trust model, current treatments of childhood obesity can lead to effective weight reduction even in the long run for many participants (4,5,6,16,17).
Flaw 2: Children WILL self-regulate food intake effectively when exposed to unlimited quantities of highly desirable foods.
Evidence indicates: Children will NOT self-regulate food intake effectively when exposed to unlimited quantities of highly desirable foods.
Eneli et al. recognized this as an “area of weakness” in the trust model (1; p. 2199). They correctly indicated that research has shown that large portion sizes lead to high levels of consumption without awareness (36). Other related studies show that people are unaware of the powerful influence that the eating behaviors of others have on their own intake (37). In these studies, people modeled their food intake based on the behavior of others, eating more or less depending on their partner's consumption—regardless of whether they had not eaten in a long time or consumed a meal just prior to the experiment. In addition, caloric density (volume and weight of food) clearly impacts eating also without awareness. Furthermore, research with animals—sometimes called the “supermarket studies”—shows that providing ad lib access to high fat foods consistently produces obesity, not self regulation (38).
Children who are predisposed genetically to become overweight (which may include most children who become obese (39)), may have especially great difficulty with the trust model's plan to encourage self-regulation in the face of a wide variety and unlimited quantity of high fat food. As Lowe (13) concluded in his review concerning this issue, “[The] modern food-abundant environment may be particularly “toxic” to those who are overweight or prone to become overweight” (p. 49S).
Flaw 3: Eating IS determined by accurate recognition of internal hunger cues; such internal recognition IS necessary for effective weight control.
Evidence indicates: Eating is NOT determined by accurate recognition of internal hunger cues; such internal recognition is NOT necessary for effective weight control.
In 1968, Schacter proposed an internal/external theory of obesity, asserting that obese people are more responsive to external food cues and less responsive to internal cues of hunger (40). The internal aspect of this conceptualization has been abandoned by most researchers, including Schacter and his associates, because it turned out to be overly simplistic (41). Both lean and overweight people do not recognize internal cues of hunger or deprivation accurately (13,41). Furthermore, the biological challenges faced by obese people make it clear that obese individuals and formerly overweight people would not want to focus on their internal cues, even if they had good access to them; their excess fat cells, hormones, and enzymes, if left unchecked by deliberate efforts to regulate them, promote weight gain, not reduced eating and weight loss (13,14,21).
Flaw 4: Limiting consumption of fat is NOT critical to successful weight loss by overweight people.
Evidence indicates: Limiting consumption of fat IS critical to successful weight loss by overweight people.
Eneli et al. assert, “The trust model's lack of strict restriction of dietary fat may explain why it [the trust model] would be effective for obesity prevention and treatment” (1; p. 2199). Successful weight controllers in the National Weight Control Registry, on an average, consume 30% less fat than typical Americans (13,42). When these masters of weight control increase their consumption of fat slightly (as well as decrease activity) they tend to regain some weight (25). In addition, numerous reviews both of the animal (43) and human (44,45) research indicate to the present authors that substantially reduced fat intake seems important for effective weight loss and maintenance of reduced weight.
Flaw 5: The trust model CAN help overweight children lose weight.
Evidence indicates: Not one study over the 20+ years since the trust model was proposed has shown that the trust model can help overweight children lose weight.
Eneli et al. acknowledged this problem and were not able to cite evidence—not even a series of cases or an uncontrolled cohort study—that demonstrated the ability of this approach to help obese children lose weight. We also completed a literature search to verify the lack of empirical evidence for the trust model (2 November 2008). This search of Academic Search Complete, ArticleFirst (OCLC), PsycInfo, EBSCO, and Medline retrieved 35 articles referencing Satter and the trust model, 23 of them written by Satter. Satter's papers were mostly explanations, pamphlets, and descriptions of her model. Articles not written by Satter included theory papers, a validity study of Satter's Eating Competency measure, and various book reviews. Confirming Eneli et al.'s conclusion, this search found no studies investigating Satter's model.
In contrast to this lack of evidence regarding the trust model, dozens of controlled studies have tested the efficacy of family-based cognitive-behavior therapy on childhood obesity. In numerous qualitative and quantitative reviews, researchers conclude that these treatments produce significant changes in weight (4,5,6,16,17). For example, Wilfley et al.'s careful meta-analysis (16) showed that children in waitlist or educational comparison groups tended to increase their percent-overweight at follow-up by 2.9%, whereas children in treatment programs decreased percent-overweight by 8.9% at follow-up. Moreover, the effect size at follow-up showed that children in treatment had better outcomes than 82% of those in control or comparison conditions. More intensive interventions, including longer treatments and those that immerse children in nearly ideal weight controlling environments (i.e., immersion programs), may produce especially favorable outcomes (6,16,28). A panel of experts convened by 15 professional health-care groups published similar conclusions in Pediatrics in December 2007 (8). Although these treatments have demonstrated clinically meaningful efficacy, many participants do not achieve substantial improvements in the long run. Additional research and theorizing is certainly warranted to determine which participants benefit most from which approaches, and how to maximize outcomes more generally.
Satter's concern about the potential backfiring associated with traditional treatments of childhood obesity resulted in the subtitle of her most recent book on the trust model: “Helping without Harming” (3). The scientific evidence suggests, however, that following the trust model to treat obese children would most likely prove ineffective, resulting in additional failure experiences for overweight children and their parents. Research on the trust model as an approach to treating childhood obesity will probably lead to a dead end. Perhaps the lack of documentation of the effects of this model over the past twenty years suggests that the dead end has already been reached. Alternative conceptualizations and interventions that are much more closely aligned with science have demonstrated far greater promise.
The childhood obesity epidemic has blossomed in full force since the initial publication of the trust model. In view of the urgent need to provide effective interventions for the millions of obese children in the world, is it not more harmful than helpful to pursue an inadequate model?
We gratefully acknowledge the helpful comments provided by Elissa Jelalian on an earlier draft of this paper.
The authors are employees of Wellspring, a leading provider of behavioral health treatment to obese and overweight children and adolescents; thus, this comment may reflect some philosophical bias pertaining to treatment methods and efficacy.
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