Telecoaching plus a portion control plate for weight care management: a randomized trial

We conducted a randomized clinical trial evaluating the effectiveness of telecoaching combined with a portion control plate. Telecoaching was provided during a 3-month intervention period with follow-up through 6 months after randomization. The primary study outcomes were weight reduction, BMI, waist circumference, and waist to hip ratio, measured at 6, 12, 18, and 24 weeks. Secondary outcomes included measures assessing eating behaviors, self-efficacy, and physical activity collected at 12 and 24 weeks. Enrollment took place between May 2011 and June 2012. This trial was performed in accordance with the CONSORT guidelines for randomized controlled trials (see Additional file 1 and 2 for details).

The study was conducted at a large academic primary care practice in the Midwestern United States. The practice provides primary care to approximately 130,000 patients.

Participants were eligible for the study if they were between the ages of 18 and 55 years with a body mass index ≥30 and ≤39.9 kg/m² (obesity class I and II) and were motivated to pursue weight loss. We selected the upper age limit of 55 years because we were most interested in determining if the intervention was effective in a population at risk for complications related to overweight and obesity who may not yet be suffering these consequences. Participants were excluded if they had a significant health condition (for example, recent myocardial infarction, untreated hypertension, bipolar disorder, etcetera), had undergone bariatric surgery, were pregnant, or were utilizing an investigational weight loss medication. This study was approved by the Institutional Review Board of Mayo Clinic prior to patient contact: reference number 11-001395.

Study personnel performed a limited chart review based on BMI and age eligibility criteria to identify primary care patients eligible for the study. For potentially eligible participants who had an upcoming appointment, their primary care providers were alerted of their eligibility. The study was then introduced at the clinic visit with referral of those interested to study personnel for consideration of enrollment. For eligible participants who did not have an upcoming appointment in primary care, a recruitment letter was sent with instructions on how to contact study personnel for enrollment. All interested eligible patients underwent initial pre-screening via telephone by study personnel. Potential subjects then met with study personnel to review the study protocol in detail. Informed consent was obtained from all participants (or next of kin) prior to enrolment in the trial.

A computer generated randomization schedule was created using blocks of size 4 to ensure that treatment assignment was balanced across groups over the course of the enrollment period. Using this randomization schedule, individuals who did not have any subject contact for the present study prepared randomization envelopes, which were labeled according to subject ID number and contained an index card indicating the treatment assignment for the given subject. At the time of enrollment, a subject was assigned the next sequential subject ID number, and the appropriate sealed envelope was opened to reveal the subject’s randomized treatment assignment. The authors were blinded to randomization. The interventionist was not blinded to study assignment given the nature of the intervention Additional files 3.

In the intervention group, participants received a portion control plate with instructions on use along with telecoaching. Telecoaching involved telephone counseling on lifestyle modification from a single master’s level female counselor trained in motivational interviewing and wellness coaching.

The wellness coach proactively contacted the participants every 2 weeks for 3 months for a total of seven phone calls. Motivational interviewing was the framework for intervention delivery. Motivational interviewing is a directive, patient-centered counseling style for eliciting behavior change by helping patients to explore and resolve ambivalence [24], with efficacy data for weight loss in face-to-face clinical settings [25]. The focus of the discussion was an improvement in lifestyle by identifying barriers to incorporating healthy behaviors and problem solving to overcome these, collaborative goal setting, and progress toward patient-identified behavior change goals. Specific strategies were utilized to focus on improving diet and physical activity. These included, giving information about the “500 calorie challenge,” which is a strategy for reducing daily caloric intake by 500 calories. Additionally, recommendations were given for incorporating routine self-weighing, tools for monitoring and documenting intake, and regular physical activity with a goal of 150 min of moderate intensity exercise per week.

Average phone call duration was approximately 20 minutes with the first and final calls being slightly longer. The format of the coaching session was a “check in,” focusing on progress towards behavior change goals from the previous call, discussion around successes and barriers, problem solving, and collaboratively setting an action plan for the upcoming 2 weeks. The usual care group received institutional pamphlets on healthy eating and exercise habits.

Participants in both groups were evaluated in the clinic at baseline and at 6, 12, 18, and 24 weeks to obtain weight, BMI, waist circumference, and waist to hip ratio. Participants also completed measures assessing eating behaviors and physical activity at baseline and at 12 and 24 weeks.

The primary outcomes included body weight, BMI, waist circumference, and waist to hip ratio. Body weight was measured by a digital scale calibrated on a regular basis using certified weights. Participants were measured with their shoes and heavy outer garments removed and pockets emptied. The BMI was calculated from measured height and weight (kg/height [meters]²). Waist circumference measurement was standardized utilizing a measuring tape held in the horizontal plane around the abdomen at the iliac crest and taken at the end of a normal expiration with the tape snug and not compressing the skin. Waist to hip ratio was calculated by dividing the waist circumference measurement by the measurement obtained at the narrowest part of the hips.

Secondary outcomes included physical activity level, dietary changes, self-efficacy, social support, and constructs of behavioral change. Physical activity was measured via two separate surveys. The Seven-Day Physical Activity Recall [26] is a five-item assessment of physical activity over the previous 7 days that characterizes sleep, light, moderately hard, hard, and very hard activity. Results are reported as total daily energy expenditure (kcal/day). The International Physical Activity Questionnaire (IPAQ) [27] is a seven-question self-report measure of physical activity that has been shown valid and repeatable in very diverse settings throughout 12 different countries. The questionnaire assesses frequency and duration of walking, moderate-intensity activity, and vigorous-intensity activity over a 1-week period, with results reported in total Metabolic Equivalents (METs) per week.

Dietary changes were measured via the Food Frequency Questionnaire (FFQ), which is a self-administered food questionnaire that asks the participant to report frequency of consumption and portion size of 125 common food items over a given time [28, 29]. This was administered electronically.

The Eating Inventory [30] measured dietary restraint, disinhibition, and hunger. Research has demonstrated that scores can improve following obesity treatment, and that scores predict outcome to obesity treatment [31]. Additionally, we utilized the Weight Efficacy Life-Style Questionnaire (WEL) [32], which is a 20-item eating self-efficacy scale consisting of a total score and five situational factors: negative emotions, availability, social pressure, physical discomfort, and positive activities. Participants rated their confidence in being able to successfully resist the urge to eat using a 10-point scale ranging from 0 (not confident) to 9 (very confident) [33]. Improvements in eating self-efficacy have been associated with both greater weight loss as well as improved performance in weight control behaviors during intensive treatments [34]. We measured social support with the Weight Management Support Inventory (WMSI) [35], which assesses four dimensions of social support (emotional, instrumental, informational, and appraisal). The WMSI allows measurement of baseline levels of support for weight management and verifies changes in support via intervention. Finally, we measured commonly accepted constructs of behavioral change with the Neis Behavior Change Scale (NEIS), which is a 16-item questionnaire that evaluates three theoretical constructs: (a) goal setting, (b) restructuring plans, and (c) relapse prevention and maintenance. These constructs have previously been identified as important aspects of interventions, and this scale has been shown to have both internal and test-retest reliability in assessing these [36].

Of the 1101 subjects screened, 106 passed a telephone pre-screen. Of these 106, 92 attended a consent/screen visit, and 90 were randomly assigned to telecoaching plus portion control plate (n = 45) or usual care (n = 45) (Table 1). Although the majority of both treatment groups were female, the percentage of males in the telecoaching plus portion control group was significantly lower than that for the usual care group (16 % versus 36 %; P = .030). Other baseline characteristics were similar between groups. Fourteen subjects discontinued the study, as they were not present for the 6-month follow-up visit resulting in an overall study completion rate of 84 % (82 % for telecoaching plus portion control, 87 % for usual care).

In the primary analysis using last-value carried forward without adjustment for baseline demographics, significant reductions in BMI (estimated treatment effect -0.4 kg/m², P = .038) and waist to hip ratio (estimated treatment effect -.02, P = .037) at 3 months were observed in the telecoaching plus portion control plate group compared to usual care (Table 2). These differences were not statistically significant at 6 months.

Because the distribution of males and females was found to differ significantly between treatment groups, post-hoc analyses with last-value carried forward were performed with sex included as a covariate. For the endpoints of weight and BMI, significant sex-by-treatment interaction effects were detected at both 3 months (P = .027 and P = .049) and 6 months (P = .020 and P = .044). Given these significant sex-by-treatment interaction effects, additional analyses were performed to assess all endpoints separately for males and females. For females, the telecoaching plus portion control intervention was associated with significant reductions in weight and BMI at both 3 (estimated treatment effect -1.6 kg, P = .016 and-0.6 kg/m², P = .020) and 6 months (estimated treatment effect -2.3 kg, P = .013 and -0.8 kg/m², P = .025). For males, the telecoaching plus portion control intervention was associated with a significant reduction in waist to hip ratio at 3-months (estimated treatment effect -0.04, P = .017).

We observed no significant overall difference in physical activity, dietary quality, or theory-based measures between the intervention and usual care groups. Among women, significant differences were observed for the change in METs per week based on the IPAQ (median change from baseline +778 versus -257 for telecoaching plus portion control versus usual care, respectively; P = .011), change in WEL total score (+12.5 versus -1.5, P = .041) and change in NEIS restructuring plans (+1.0 versus -1.0, P = .012) (Table 3).