Two Self-Directed Intervention Weight Loss Programs

The latest data indicate that 1 in 3 Americans is obese, and almost 2 of 3 Americans are either overweight or obese. Many weight loss programs use a clinic-based model, where participants attend regularly scheduled meetings, usually in the evening. Attending these programs can be problematic, including commuting problems, need for child care, and general costs of materials.

As a result, alternate approaches have been tried, including use of the Internet, telephone follow-up, e-mail, and regular mail. These interventions generally lead to a 5% weight loss(JAMA 2003; 289:1833) Dr. Bryan K. Smith and a team of University of Kansas researchers recently compared the effectiveness of two home-based weight loss interventions that differed only in the amount of outside support (Obesity Research & Clinical Practice 2009; 3:149).

Limited support group

In a 12-week randomized controlled study, one group of 37 participants received limited support with a single 10-minute phone call each week. A second group had no weekly support, and a control group received no components of the study. Both study groups received the same low-calorie, high-volume diet of 1200 to 1500 kcal/day, composed of prepackaged meals, shakes, and fruit and vegetables. The participants also received information about exercise and exercise goals (2000 kcal/week). The study participants were from 19 to 70 years of age and had a body mass index (BMI) between 25.0 and 39.9 kg/m2. Height, weight, waist and hip circumference were measured at baseline and at the end of the study.

Intervention groups

In the intervention groups, participants received an instructional booklet in the mail prior to the study. The booklet contained details about the diet, sample menus, suggestions for adding variety to the low-calorie shakes and prepackaged meals, as well as weekly progress charts and answers to commonly asked questions. A health educator also telephoned all the participants with a 45-minute call at the beginning of the study. The participants were instructed to record the prepackaged meals, shakes, fruits and vegetable intake and energy expenditure each day on the progress charts.

Those in the limited weekly intervention group received one 10-minute telephone call from an experienced health educator each week during the 12-week intervention. The main reason for the call was to track adherence with the program by having the participant report weekly intake and exercise totals. At the end of the study, all participants filled in a 15-item exit survey to measure the effectiveness of all the study components, including the initial telephone call and the printed materials, and to gauge their overall satisfaction with the program.

More overall success with limited intervention

All 93 participants completed the study. There were no significant differences between the three groups in any of the baseline characteristics of the 22 males and 71 females. The decreases in body weight, BMI and hip and waist circumference were greater in both intervention groups compared to the control group, and the mean percent weight loss in the limited-intervention group was significantly greater than in the nonintervention group. In the limited-intervention group, 37% of participants lost between 5% and 10% of their initial body weight, while 7% of those in the nonintervention group lost more than 5% to 10% of their initial weight. Those in the limited-intervention group also did a much better job of filling out their weekly reports—97% filled out at least one report, compared with 39% of those in the non-intervention group. The limited-intervention group also consumed significantly more shakes, prepackaged meals and fruits and vegetables than did the nonintervention group. Actual mean weight loss and percent weight loss for the limited-intervention group, the nonintervention group, and the control group were: 7.7 kg (4.2%), 5.9 kg (4.2%), and 1.9 kg (1.2%), respectively.

Success factors

The authors feel that several factors might have contributed to the success of the home-based weight loss program. First, the program used prepackaged meals and shakes were provided and delivered directly to each participant, eliminating time, expense, and expertise necessary for purchasing self-selected foods. There is growing evidence, according to the authors, that prepackaged foods increase percentage of weight loss in such programs (Arch Intern Med 2006; 166:1620; JAMA 2001; 289:1833).

Although the combination of weekly intervention and self-monitoring might be credited with the success of the limited intervention, the authors believe that it is more likely due to the combination of elements—a low-calorie diet, packaged meals, physical activity, individual support, and record-keeping. The weekly 10-minute telephone call may have contributed to the additional weight loss; the participants also mentioned that weekly progress charts provided positive feedback and encouragement.

Certain elements need further examination, according to the authors—one area for further study is the cost associated with typical home-based programs. Treatment costs can be substantial and become higher as the complexity of a program increases. Although a formal cost analysis was not part of this study, the authors estimate that the costs for materials and phone calls, and not counting the cost for meals, were about $35 for the nonintervention group and only $86 for the limited-intervention group.