Addictive Behaviors, Vol. 9, pp. 279-285, 1984 Printed in the USA. All rights reserved.

0306-4603/84 $3.00 + .OO Copyright o 1984 Pergamon Press Ltd

MINIMAL INTERVENTIONS FOR WEIGHT CONTROL: A COST-EFFECTIVE ALTERNATIVE

DAVID R. BLACK University of Nebraska Medical Center

WILLIAM C. COE California State University Fresno

JAMES G. FRIESEN Shepherd’s House Inc.

ANDREA G. WURZMANN California State University Fresno

Abstract-Two studies were conducted to evaluate simpler, less intensive interventions for weight control which presumably would be more cost-effective and efficient than a “full- length” behavioral treatment program. In Study 1, participants in a minimal intervention (MH) program who attended no regularly scheduled meetings and initially only received three simple verbal instructions about how to lose weight, lost an average of 11.1 lb. by ‘I-month follow-up. Subjects in three variations of a shortened, less intensive, dweek behavioral weight loss program lost 7.8, 6.5 and 6.3 lb. but did not significantly differ from MI1 subjects in the amount of weight lost. In Study 2, MI2 subjects lost 5.5 lb. compared to subjects in two varia- tions of a full-length program who lost 8.1 and 11 .l lb. by 6-month follow-up. Again, none of the groups significantly differed from each other in the amount lost. It was concluded that a minimal intervention program seems to produce weight loss and to be a cost-effective and effi- cient method for some subjects. The difference between the two minima1 intervention pro- grams may be related to the payment of a monetary deposit; a model for future research was presented to investigate simpler, less intensive interventions in combination with more complex ones in a “stepped-care” fashion.

The prevalence of obesity for adults in the United States is estimated to range from 15% to 50% (Bray, 1976; Van Itallie, 1977) with over 20 million Americans seeking to lose weight (Stuart 8c Davis, 1972). Small-group behavior therapy procedures admin- istered in clinic settings have been used most often to treat this problem (Abrams & Follick, 1983; Wilson & Brownell, 1980). The drawbacks of such programs are that they are often expensive to administer, time consuming for the counselor and may be intrusive to the participant’s everyday life (Jeffery & Gerber, 1982; Kasl, 1980; Wing & Epstein, 1982).

A more cost-effective and efficient way to meet the demand for treatment might be to use simpler, less intensive interventions. Investigators working with hypertensive pa- tients have found that a minimum of intervention seems to substantially reduce blood pressure. Home self-measurements of blood pressure have been found to result in a decrease of blood pressure similar to what might be expected if someone attended treat- ment sessions in which relaxation training was provided (Laughlin, Fisher, & Sherrard,

The authors wish to thank Rena R. Wing, Mark E. McKinney, Ronald S. Hadsall and William E. Threlfall for their suggestions and comments on earlier drafts of this manuscript. The authors also wish to express their gratitude to Don Turner, who served as a counselor in Study 2.

Requests for reprints should be sent to David R. Black, Department of Preventive and Stress Medicine, University of Nebraska Medical Center, 42nd and Dewey Avenue, Omaha, NE 68105.

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280 DAVID R. BLACK et al.

1979). Other researchers have found that if patients are simply told to relax that their blood pressure decreases as much as patients who receive blood pressure or electromyo- graphic feedback (Blanchard, Miller, Abel, Haynes, & Wicker, 1979). Others have found that the greatest decline in blood pressure occurs during baseline before imple- menting behavioral treatment programs (Surwit, Shapiro & Good, 1978). Periodic blood pressure monitoring at a clinic has also been noted to produce blood pressure changes that appear to be similar to those of behavioral treatment programs (Hovell, Geary, Black, Kamachi, & Kirk, in press; Jacob, Fortmann, Kraemer, Farquhar, & Agras, in press).

To apply the minimal intervention concept to weight control, a person might receive little counselor contact or instruction about how to lose weight and would not be seen for regularly scheduled treatment sessions. Another example of a simpler intervention might be a shortened and less intensive (fewer sessions) behavioral weight loss pro- gram. The typical length of a behavioral program is 10 to 12 weeks (M = 10.6) (Wilson & Brownell, 1980) and the behavioral components usually included in such programs are those of self-monitoring, nutritional information, stimulus control techniques, some form of self-reward, coverant techniques, relaxation training, physical activity and family support (Glasgow & Rosen, 1978). A program that reduced the number of sessions by approximately 50% and incorporated a few of the components listed above might be an effective, efficient and less demanding alternative for weight control. It also seems important to compare the weight loss results of minimal or shortened in- tervention with a full-length behavioral program that contains most of the components listed above. Some variations of methods of motivation often used in community and clinic programs might also be varied in the full-length treatment (cf. Jeffrey & Christensen, 1975; Kingsley & Wilson, 1977).

Two studies were conducted in an attempt to meet the demands for treatment and to develop a low-cost, effective alternative for weight control by using less intensive and “simpler” interventions rather than more complex ones. In the first study, the primary objective was to determine if a minimal intervention program would produce weight loss and whether a minimal or shortened intervention would be best. In the second study, the objective was to compare the program producing the best results in Study 1 with a “standard” full-length behavioral program emphasizing motivational methods similar to those that might be found in a community or clinic setting.

METHOD

Subjects Participants were recruited through physicians and an announcement in a university

newspaper. To be eligible to enroll in one of the two studies, a person had to be at least 20% overweight according to the Metropolitan Life Insurance Chart (1960) and medically cleared to participate which meant a physician signed a statement indicating the potential subject had no physiological or medical problems that would inhibit weight loss. There was a total of 113 participants; 47 in Study 1 and 66 in Study 2. Sub- jects were randomly assigned to treatment conditions from stratified blocks based on percentage overweight. Subjects in Study 1 initially ranged in age from 18 to 52 years old (M = 32.9), weighed 141 to 302 lb. (M = 188.9) and were 21% to 87% overweight (M = 53.2). In Study 2, subjects were initially 18 to 61 years old (M = 34.4), weighed 145 to 275 lb. (M = 186.8) and were 21% to 93% overweight (A4 = 74.8). The per- centage of women in each study was 91.5% and 80.3%, respectively.

Minimal interventions for weight control 281

Procedure

Minimal intervention programs. Subjects in the minimal intervention program in Study 1 (MIl) (n = 11) and Study 2 (M12) (n = 22) were seen only for weigh-ins. Both groups were weighed initially and MI1 subjects were seen 6 weeks later and MI2 sub- jects 10 weeks later. These times corresponded with the posttreatment sessions for sub- jects in the shortened or full-length interventions in Study 1 and 2, respectively. MI1 subjects were also seen again 7 months later and MI2 subjects were seen 6 months later which corresponded with follow-up meetings scheduled for subjects in the other groups in Study 1 and 2, respectively.

Those subjects who were selected for the MI1 or MI2 program were telephoned and told they had been randomly assigned to this condition and that they would not be seen regularly by a counselor. They were instructed not to contact another professional or enroll in other weight loss programs but were encouraged to lose weight on their own. If they wished to reduce, they were to do the following: (a) eat a nutritious, well- balanced diet from the four basic food groups, (b) find ways to increase physical activity without necessarily engaging in strenuous exercise, and (c) lose weight slowly and gradually at a rate not to exceed two pounds a week. Reasonableness and safety were the watch words. Subjects were further advised that if they experienced any adverse ef- fects, they were to contact the clinic immediately (none did). After the follow-up ses- sion, copies of the behavioral treatment materials used with subjects in the shortened or full-length groups were mailed to MI1 and MI2 subjects.

The only difference between the two minimal intervention programs was MI1 sub- jects (like all subjects in Study 1) paid a $35.00 deposit and MI2 subjects (like all sub- jects in Study 2) paid no deposit. MI1 subjects were refunded $25.00 shortly after they were assigned to this condition since they were not going to be seen regularly by a counselor and $5.00 was refunded at the posttreatment as well as the follow-up session for weighing in.

Shortened behavioral programs. Subjects in Study 1 assigned to the shortened behavioral programs met once a week with a counselor for 60 to 90 minutes for 6 con- secutive weeks and were seen at a 7-month follow-up meeting. They received $5.00 of their deposit for attending each treatment session and the follow-up meeting. The third author, a graduate student in clinical psychology at the time of the study, was the counselor for each of these groups. Subjects assigned to the basic program (BP) (n = 13) were didactically taught four components: self-monitoring, nutritional counseling, physical activity and social support (cf. Mahoney & Mahoney, 1976). Sub- jects enrolled in the second shortened program learned the basic program plus stimulus control techniques (BP + SC) (n = 12) and subjects in the third program were taught the basic program along with cognitive restructuring techniques (BP + CR) (n = 11) (cf. Mahoney & Mahoney, 1976).

Full-length behavioral programs. Subjects in Study 2 assigned to the full-length behavioral treatment programs met once a week with a counselor for 90 minutes for 10 consecutive weeks and were seen again at a 6-month follow-up meeting. The fourth author and another graduate student in clinical psychology at the time of study were the counselors for both behavioral programs. The only difference between the two pro- grams was in motivational emphasis. The first program emphasized group reliance (GR) (n = 22) and subjects were told to support and encourage each other. Group competition was fostered at each session by weighing subjects publicly and placing a symbol on a large chart to indicate gain, loss or maintenance of weight. The person los-

282 DAVID R. BLACK et al.

Table 1. Pounds lost for subjects who completed each time period in study 1 and study 2.

Pre to post Post to follow-up Pre to follow-up

Group n M SD n M SD n M SD

Study 1 MI1 9 3.36 7.58 7 7.71 7.63 7 11.07 13.21 BP 11 3.33 3.19 9 4.50 7.19 9 7.83 8.18 BP + SC 11 2.50 2.91 10 3.95 11.56 10 6.45 12.86 BP + CR 9 2.94 5.13 8 3.38 5.79 8 6.31 9.38

Study 2 Ml2 20 3.15 5.41 17 2.37 7.76 17 5.52 9.58 CR 17 10.84 6.96 16 2.73 3.62 16 8.11 7.30 SR 17 8.47 6.49 16 2.58 8.20 16 11.05 9.83

Note: In Study 1 the original n six was 11, 13, 12, and 11 subjects in the Mll, BP, BP + SC and BP + CR groups, respec- tively. The initial n size was 22 subjects in each group in Study 2.

ing the most weight each week was given a paper crown to wear during the session (cf. Kingsley & Wilson, 1977). The second program emphasized self-reliance (SR) (n = 22) and subjects were told to use “will power” and not to rely or be dependent on other group members for support. To reinforce independent functioning, subjects were weighed privately behind a screen at each session. The counselor did not comment on weight gain or loss and changes in weight were posted on personal weight progress charts (cf. Jeffrey & Christensen, 1975). In both programs subjects were taught the fol- lowing eight components: self-monitoring, nutritional counseling, stimulus control, relaxation training, physical activity, cognitive restructuring, self-reward and social support engineering (cf. Mahoney & Mahoney, 1976).

RESULTS

Attrition Table 1 shows the number of subjects in each group who remained in both studies

over time. A simple chi-square test shows that the proportion who completed Study 1 (72.3%) and Study 2 (74.2%) was similar. In both studies, complex chi-square tests demonstrate that the number of subjects remaining in each group at each time period was not significantly different. A one-way analysis of variance (ANOVA) or the ap- propriate nonparametric equivalent also shows that the groups did not significantly differ initially or after attrition on the initial group composition variables of age, percentage overweight and absolute body weight. The same result is found when a complex chi-square test is computed for sex. Therefore, the drop out rate appears to be equivalent over time between studies and between groups within studies. The groups are also equivalent on initial group composition variables initially and after attrition.

Weight changes Table 1 also shows the number of pounds lost at each time period for subjects remain-

ing in each study. In Study 1, subjects in the MI1 group lost 11 .l lb. by the end of follow-up and those in the BP, BP + SC and BP + CR lost 7.8, 6.5 and 6.3 lb., respectively. A repeated measures ANOVA showed no significant differences between

Minimal interventions for weight control 283

groups in the amount lost over time and the interaction effect was not significant. The main effect for time was also not significant.’

In Study 2, MI2 subjects lost 5.5 lb. by 6-month follow-up and those in the GR and SR groups 8.1 and 11 .l lb., respectively.2 A repeated measures ANOVA showed no significant difference between groups in the amount of weight lost by follow-up. All groups lost a significant amount of weight over time, F (1,46) = 21.89, p c .Ol, and there was a significant interaction effect, F (2,46) = 6.93, p c .Ol. Newman-Keuls analyses showed that both GR and SR groups lost more weight than the MI2 group at posttreatment (p < .Ol, .05, respectively), but during the 6-month follow-up period the MI2 and SR groups lost significantly more weight than the GR group (p < .05).

DISCUSSION

The authors recognize that a finding of no difference between groups does not mean that the groups are not actually different because the null hypothesis can only be re- jected not accepted. However, the study has heuristic value because of the reduction in counselor time and the presumed cost-effectiveness of the minimal intervention pro- gram. In addition, the amount of weight lost by MI1 subjects is equivalent to the 11.5 lb. average usually reported in the behaviorial weight loss research literature (Wing & Jeffery, 1979) and the amount lost in both minimal intervention programs compares favorably to follow-up results of bibliotherapy programs where subjects are given writ- ten (not verbal) instructions about how to lose weight and may or may not have periodic contacts with a counselor (Glasgow & Rosen, 1978; Marston, Marston, & Ross, 1977; Pezzot-Pearce, Lebow, 8z Pearce, 1982). Therefore, the use of a minimal intervention program may be a valid treatment for some moderately obese people and it seems that a number of subjects may lose weight when given a minimum of counselor assistance and only a few, simple verbal instructions. In Study 2, it should be noted that MI2 sub- jects started out losing weight at a slower rate than the other groups but during follow-up did better than subjects who depended on group support and at least as well as those who were encouraged to be self-reliant.

The findings do, however, raise several questions. First, it might be argued that a stronger, more powerful intervention could have been compared with the minimal in- tervention program in Study 2. It is true that the weight losses for the two full-length programs were not as great as the most dramatic results that have been reported (e.g., Black, 1984; Brownell, Heckerman, Westlake, Hayes, & Monti, 1978; Stuart, 1967). The objective though was to compare the minimal intervention program with an in- tervention that might be considered typical or standard. The weight losses for the GR and SR groups are generally within the weight range reported for behavioral weight loss studies (cf. Foreyt, Mitchell, Garner, Gee, Scott, & Gotto, 1982, Stuart, Mitchell, & Jensen, 1981; Wilson & Brownell, 1980; Wing & Jeffery, 1979).

A second question that might be raised is what MI subjects did to lose weight. Verbal reports from participants indicate that they complied with the verbal instructions about

‘A repeated measures ANOVA was also computed for changes in percentage overweight and the body mass index (weight/height3 for subjects who completed all time periods. Analyses of each of these depen- dent measures for both studies yielded the same results as the analysis for pounds lost. Therefore, pounds lost was reported in the text because it is easily understood and allows comparison with other studies.

5ince each counselor in Study 2 saw an equal number of subjects in the GP and SP groups, an ANOVA was computed which showed no significant counselor or counselor by treatment effects. A questionnaire was also administered and results of a Mann-Whitney U test showed that four of the six questions significantly differentiated GP subjects from SP subjects and indicated that GP subjects perceived their treatment as more competitive and supportive, U (17,17) = 72, 69, 76, 95; p < .05.

284 DAVID R. BLACK et al.

how to lose weight if they wished to do so. However, further inquiry ought to be made in future studies about which self-change methods subjects used and which ones they found to be most beneficial.

A third question that might arise is why MI subjects in Study 1 lost twice as much weight as MI subjects in Study 2. The only procedural difference between the two studies was that MI1 subjects paid a monetary deposit and MI2 did not. Stanton (1976) has found that the act of paying a deposit may heighten a person’s commitment and motivation to lose weight and Black and Friesen (1983) have shown that the deposit and return of money for weighing-in significantly affected the amount of weight lost by subjects in two, brief 4-month minimal intervention programs.

The fourth question might be how the minimal intervention program differs from a no-treatment control group. Subjects in no-treatment control groups usually receive no instructions about how to lose weight, are told not to change their habits in any way and to behave as if they never had inquired about a weight reduction program or planned to lose weight. The minimal intervention subjects, on the other hand, were told they could alter their habits and were given explicit instructions about what to do if they wanted to reduce.

Another question might be related to the drop out rate. The approximate 25% drop out rate in both studies is above the mean of 13.5% attrition for behavioral studies but within the 0% to 26% range reported by Wilson and Brownell (1980). Interestingly, at- trition was no less in Study 1 for subjects who paid a monetary deposit. This finding is inconsistent with Wilson and Brownell’s (1980) review that shows attrition is less if money is deposited. The reason for this discrepancy may be due to a difference in selec- tion procedures. The present studies operated similarly to a clinic because there were few restrictions for participation unlike most experimental studies where strict criteria are used.

Again heuristically, the results offer some exciting possibilities for future research. The outcome suggests the possibility of utilizing a “minimalist” approach for the treat- ment of obesity where less intensive interventions would be tried before more complex ones (Kasl, 1980). The criterion for introducing more complex methods of intervention could be based on weight loss performance. A simple, minimal intervention could be used first in this progression. For some people, this approach might be all that is neces- sary to lose a substantial amount of weight. However, if weight loss did not occur or stabilized at an undesirable level during the minimal intervention program, a second, more intensive level of treatment could be added. For example, a shortened behavioral treatment might be introduced. The fact that none of the shortened programs in this study was more effective than the MI1 group does not rule out the possibility that a reduced program in combination with a minimal intervention program might produce substantial weight losses. Finally, those people who did not lose weight or achieve their weight loss goals could receive additional components that would be equivalent to a full-treatment program. An advantage of such a progressive model or a “stepped care” approach to weight control is that people might be able to more effectively tailor a pro- gram to meet their needs and be convinced of the necessity to use more costly and time consuming interventions if they were not successful in losing weight with minimal or moderate counselor assistance. Also, some people may not need all levels of interven- tion which would result in a more cost-effective and efficient approach to weight loss and may lead to more homogeneous and clinically significant results.

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