Participants
To participate, individuals had to be between 21 and 35 years old with a BMI between 27–40 kg/m2, and could not have a history of an eating disorder or substance abuse, be participating in another weight loss program, have lost ≥ 5% of their body weight within 6 months, or be unable to participate in unsupervised exercise. For the current study we chose to exclude individuals between 18 and 20 years of age given the high proportion of college students in this age range and 1) the needs of college students may be distinct from other young adults and this group is often studied separately; 2) there are potential concerns about daily weighing and eating disorders in this group; and 3) due to ethical considerations related to the discussion of alcohol in this program with individuals who are under the legal drinking age. We selected 35 years of age as our upper limit for enrollment because data indicate that in the U.S. among adults between 25 and 74, weight gain over 10 years was highest at ages 25–35.
A total of 119 participants were screened by phone to determine preliminary eligibility (see Figure 1 for details). A total of 40 young adults were randomized to treatment (35 female and 5 male); on average, they were 29.1 ± 3.9 years old with a BMI of 33.36 ± 3.4 kg/m2 and a mean baseline weight of 82.3 ± 12.6 kg. Participants were 19.5% Hispanic, 75% Caucasian, 7.5% Black/African-American, and 17.5% Biracial or other. Baseline characteristics did not differ between the treatment conditions.
Procedure
Participants were recruited through advertisements in the local media, email blasts, and flyers posted in the Providence area. Interested participants contacted us and completed a brief phone screen to determine preliminary eligibility. Those who were eligible and remained interested were invited to attend a small group orientation visit where the details of the study were described and informed consent was obtained. Participants who consented completed baseline assessments visits at which measures of height and weight were taken, and study questionnaires were completed. Those participants who remained eligible were then randomly assigned to treatment groups.
Design
Participants were randomly assigned to one of two groups: a behavioral self-regulation condition (BSR) or a tailored version of standard behavioral treatment (SBT). Both groups met weekly for 10 weeks, followed by a booster session at week 14. Assessments took place at baseline, post-treatment (i.e., 10 weeks) and at a follow-up visit at 20 weeks. Additionally, at the follow-up assessment visit participants were asked to complete anonymous feedback forms about their experience in the Live Well program, as well as their preferences for format and duration of a weight loss program. Participants were paid $20 for completing the post-treatment assessment visit, and an additional $20 for the follow-up visit. We certify that all applicable institutional and governmental regulations concerning the ethical use of human volunteers were followed during this research. This study was approved by the Institutional Review Board at the Miriam Hospital in Providence, Rhode Island.
Common Treatment Components across Both Groups
Contact
Treatment consisted of 10 weekly group meetings, each 60 minutes in length, with an optional booster session at week 14.
Dietary goals
Daily calorie goals were based upon weight at study entry; individuals with an entry weight ≤ 91 kg were prescribed 1200 kcals/day and those with an entry weight of > 91 kg were prescribed 1500 kcals/day. Participants also were given a target of no more than 20–30% calories from fat.
Exercise goals
Research has demonstrated that young adults, in particular, are at risk for decreasing their physical activity. In fact, rates of physical activity appear to decline significantly during the transition from adolescence to adulthood [26]. Therefore, the importance of physical activity was stressed throughout the current program. Participants were instructed to gradually increase their physical activity until they were active at least 40 minutes a day 5 times per week. To minimize barriers for physical activity, participants were encouraged to do brisk walking and were allowed to accumulate time spent being physically active by engaging in multiple short bouts (e.g., at least 10 minutes in length).
Behavior modification skills
Participants were instructed in core behavioral and cognitive skills, which form the basis of behavioral obesity treatments and are used to help participants implement changes in eating and activity behaviors (e.g., self-monitoring, stimulus control, goal setting, relapse prevention).
Tailoring of session content
Lessons were adapted to place greater emphasis on problematic behaviors of particular relevance to this age group. For example, fast food consumption increases as adolescents become young adults [27], and fast food consumption and change in fast food consumption is related to the magnitude of weight gain and obesity in this age group [28, 29]. Also, data indicate that high percentages of young adults consume sweetened beverages, which can result in excess calories [30]. Finally, there are high rates of alcohol consumption in this age group [11], which can result in excess calories consumed both from the calories contained in alcohol, and from increased disinhibition and eating that occurs after consuming alcohol. Examples of other issues covered include social eating, peer pressure/influences, and effective time management.
Treatment Components Unique to SBT
Weighing prescription
Participants in the SBT group were instructed not to weigh themselves at home during the active treatment phase of the program. They were weighed by the intervention staff in private just before each of the weekly group meetings. After treatment ended, they were encouraged to weigh themselves weekly at home to continue to monitor their progress, but were reminded to place primary emphasis on their behaviors, not on their weight.
Maintenance plan
During the last group meeting, interventionists worked with participants to help them formulate goals and an action plan for the next month. Within the context of a relapse prevention lesson, they were encouraged to set specific goals, develop self- reinforcement strategies, and formulate an action plan to deal with any slips they might experience. Participants were offered an optional booster session at 14 weeks to check in and reassess their goals.
Treatment Components Unique to BSR
Weighing Prescription
Participants in the BSR group were given digital memory scales that stored up to 31 days of weight information and instructed to weigh themselves at home each day using this scale. They were told to weigh at the same time each day – ideally, first thing in the morning, just after waking and without clothes. Within a self-regulation framework, participants were taught to use the scale much like one would use a blood glucose monitor. That is, they learned to look for patterns and fluctuations in their weight and used the information to determine whether adjustments in energy-balance behaviors were necessary.
Education in self-regulation and color zone system
Participants in the BSR group received education on the principles of self-regulation [31], and its previous applications to diabetes [10] and weight management [9]. Within this framework, they were taught to use the scale to self-regulate their eating and activity behaviors. Based on their weekly weight, they compared their progress to their goal and used a color zone system to determine the appropriate course of action.
The color zone system was based on the successful maintenance model of STOP Regain [9], but modified for use in a weight loss program. Specifically, participants were considered to be in the green zone if their weight loss for the week was ≥ 1 kg or their weight loss overall averaged 1 kg per week. Each week they were in the green zone they received a small green gift (e.g., green gum, green tea) to provide positive reinforcement and to model the reinforcement skills taught in class. Participants were in the yellow zone if their weight loss was less than 1 kg from the week before (unless their overall weight loss averaged over 1 kg/week), and were instructed to use problem-solving skills to return to the green zone. Participants who gained weight from the previous week or who remained at the same weight for two weeks in a row (unless they already reached their goal weight) were in the red zone and were encouraged to make additional changes to affect energy balance (e.g., increasing intensity of physical activity, using a meal replacement for one meal).
Maintenance plan
During the last group meeting, interventionists worked with participants to help them formulate goals and an action plan for the next month. Within the context of a relapse prevention lesson, they were encouraged to formulate an action plan to deal with any slips they might experience. Participants also were introduced to the concept of maintenance color zones, and encouraged to use these new color zones to evaluate their weekly progress once they had met their weight loss goal. For maintenance, the green zone was defined as being within 1 kg of their weight at the end of the program; yellow zone was defined as 1.4 kg – 1.8 kg above goal/ending weight; and red zone was defined as 2.3 kg or more above their goal/ending weight. They were given instructions regarding appropriate actions to take when in each of the color zones, and were encouraged to practice self-reinforcement when in the green zone. Participants were offered an optional booster session at 14 weeks to check in and reassess their goals.
Measures
Weight
Height and weight were measured at baseline, and BMI was calculated to determine eligibility for the current study. Weight was measured objectively at baseline, post-treatment and follow-up visits, as well as before each weekly group meeting.
Frequency of Weighing
Participants in both groups were asked to self-report frequency of self-weighing at each time point by responding to the following question: "During the past month, how often did you weigh yourself?" They were given the following response options: 1) several times a day, 2) one time each day, 3) several times a week, 4) one time a week, 5) less than once a week, 6) less than once a month, 7) never weighed myself. As an objective measure of frequency of self-weighing, participants in the BSR group were required to bring the digital memory scale provided to them to clinic after 1 month in the program and at post-treatment and follow-up.
Disordered Eating
Participants in both groups were asked to complete the Eating Disorder Examination-Self-Report Questionnaire (EDE-Q) at all time points to assess disordered eating behavior. The EDE-Q is a 38-item measure adapted from the Eating Disorder Examination (EDE), which is a structured clinical interview assessing the key behavioral features and associated psychopathology of eating disorders. The EDE-Q has excellent internal consistency and 2-week test-retest reliability for the four subscales of the EDE-Q: Restraint, Weight Concern, Shape Concern, and Eating Concern [32, 33].
Body Image
Body image was assessed at all time points using the Body Shape Questionnaire, a 34-item scale that measures concerns about body shape and feelings of fatness. The Body Shape Questionnaire has been demonstrated to have adequate discriminant validity and a 3-week test-retest reliability of .88 [34, 35].
Depression
Depression was assessed at all time points using the Beck Depression Inventory (BDI-II), a questionnaire designed to assess the cognitive, behavioral, affective, and somatic symptoms associated with depression [36]. Each of the 21 items asks participants to respond on a 4-point scale from 0 to 3, with total scores ranging from 0 (minimal) to 63 (severe). Previous studies have reported internal consistency coefficients ranging from .92 to .93 and a test-retest reliability of .93; it has been validated as a measure of depression [37], and is commonly used for clinical and research purposes.
Statistical Analyses
The primary outcome of interest was weight change at follow-up. An a priori power analysis indicated that with a conservative estimate of correlation among measures (i.e., 0.5) and a significance level of 0.05, a sample size of 36 participants would provide 90% power to detect a medium within group effect in weight change over time. Primary analyses were conducted using general linear modeling in SPSS, Version 14. Initial chi-square analyses found no significant between-group differences on demographic variables of interest (i.e., sex, race, ethnicity); and an initial one-way ANOVA on baseline weight was also non-significant. To assess the effects of treatment on weight loss and psychological variables, repeated measures ANOVAS were conducted with weight evaluated at three time points (i.e., baseline, post-treatment and follow-up) and the between-subjects factor as treatment condition (i.e., behavioral self-regulation or standard behavioral). The effects of interest were the main effect of time and the interaction of time × group. Main outcome analyses were conducted using the intent to treat principle and missing weight data was imputed using the baseline carried forward method.