Original Article

International Journal of Obesity (2007) 31, 1270–1276; doi:10.1038/sj.ijo.0803568; published online 27 February 2007

Comparison of a phone vs clinic approach to achieve 10% weight loss

J E Donnelly1, B K Smith1, L Dunn1, M M Mayo2, D J Jacobsen3, E E Stewart4, C Gibson5 and D K Sullivan6

  1. 1Energy Balance Lab and Center for Physical Activity, Nutrition, and Weight Management, Schiefelbusch Institute for Life Span Studies, University of Kansas, Lawrence, KS, USA
  2. 2Department of Preventative Medicine and Public Health, Center for Biostatistics and Advanced Informatics, University of Kansas School of Medicine, Kansas City, KS, USA
  3. 3Global Medical Affairs, Schering-Plough Pharmaceuticals, Kennilworth, NJ, USA
  4. 4TransforMED, American Academy of Family Physicians, Leawood, KS, USA
  5. 5Department of Internal Medicine, University of Kansas School of Medicine, Kansas City, KS, USA
  6. 6Department of Dietetics and Nutrition, University of Kansas School of Medicine, Kansas City, KS, USA

Correspondence: Dr JE Donnelly, Center for Physical Activity and Weight Management, Schiefelbusch Institute for Life Span Studies, University of Kansas, 1301 Sunnyside Ave, Robinson, RM 100, Lawrence, KS 66045, USA. E-mail: jdonnelly@ku.edu

Received 1 September 2006; Revised 29 November 2006; Accepted 21 December 2006; Published online 27 February 2007.

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Abstract

Objective:

 

To compare the efficacy of a phone vs a traditional face-to-face clinic approach to achieve 10% weight loss and weight maintenance.

Design:

 

Twenty-six week, randomized, controlled trial.

Subjects:

 

Twenty-four men and 72 women, ages 25–68 years, with a body mass index (BMI) of 33.2plusminus3.8.

Measurements:

 

Weight loss at 12 weeks and weight maintenance at 26 weeks were the primary outcomes. Attendance, meal replacements (MRs), fruits/vegetables (F/V), and physical activity (PA) were measured weekly for process evaluation.

Results:

 

Median weight loss (range) from baseline at 12 weeks was significantly different for phone at 10.6 kg (16.6) or 10.4% and clinic at 12.7 kg (19.9) or 13.7%, and both were significantly different when compared with the control group with a weight loss of 0.25 kg (5.6) or 0.24%. Median weight loss at 26 weeks was 12.8 kg (23.4) or 13.0% from baseline for the phone group and 12.5 kg (35.2) or 12.6% from baseline for the clinic group (P>0.05).

Conclusion:

 

The median weight loss for both phone and clinic groups at 12 and 26 weeks exceeded the NHLBI guideline of 10% weight loss from baseline. The phone approach may be a viable option to the traditional weight management clinic for both service providers and participants.

Keywords:

weight management, meal replacements, diet, exercise

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Introduction

Obesity is one of the most serious and prevalent public health problems of the twenty-first century. Nearly two in three US adults are overweight and one in three are obese.1 Obesity is associated with a decreased life expectancy, increased risk of comorbidities, such as heart disease, diabetes, hypertension and some cancers, and burgeoning health care costs.2, 3, 4 It appears that few people who manage to lose weight can keep it off long term, and even embarking on a weight-loss program is difficult for many.5

The conventional algorithm of diet, exercise and behavior therapy typically requires multiple clinic visits, often time consuming and costly for the participant, and thus contributing to a high attrition rate.6 Barriers to accessing traditional clinic care include lack of transportation, a need for childcare and time conflicts with other commitments such as work, family or school.7, 8 Other barriers include the perceived cost and the reluctance to invite public exposure by openly seeking help for weight loss. Most would agree that behavior change is critical to successful weight control;9 however, it is this aspect that essentially requires some level of third-party intervention and is problematic in disseminating weight-loss programs to the general population.

The need for strategies to deliver weight management programs outside a clinic setting has resulted in weight management programs through the avenues of mail, telephone and home computers (internet and e-mail).10, 11 Although mail-mediated programs can communicate a large amount of information to a large number of people, their ability to motivate long-term changes in health behaviors is unknown.12 Phone-based programs have been limited to individual counseling and have shown moderate success to date. For example, Sherwood et al.11 have shown an approx2.4 kg weight reduction in 9 months.

The use of the internet holds some promise for the mass dissemination of information and communication at a rapid rate. For example, Tate et al.13 showed approx5 kg weight loss at 6 months for an automated computer feedback approach, compared with a human e-mail approach that showed approx7 kg weight loss and a no counseling group that showed 2.6 kg weight loss. These results are encouraging for those who have computer access and configuration compatibility with the weight-loss internet program. However, despite the widespread notion that everyone has as computer, only 50% of households surveyed by the US. Census had a computer with internet access, and the majority of households without computers fell into the lower socioeconomic range.14 Even in homes with computers, compatibility and download time with internet-mediated information can be variable and unreliable depending on the configuration in each home. Also, except for chat rooms, there is little opportunity to interact with others in a timely fashion.

The use of the phone for weight management may have some advantages compared with mail or computer-based interventions. Virtually every household has at least one landline or cellular phone.15 The phone maintains a personal connection between the program leader and the participants. Conference call technology allows participants to interact with each other in real time; yet, preserves a sense of anonymity that some may prefer. Previously, telephone interventions have shown modest success using individual counseling to promote physical activity (PA),16 and for counseling individuals with cardiovascular disease.17 Recently, Jeffery et al.18 have used the telephone to counsel for weight loss, and found an average of 2.4 kg weight loss at 6 months for the phone intervention compared with 1.9 and 1.5 kg for a mail intervention or standard care.

This randomized controlled trial (RCT) sought to determine the efficacy of a weight loss intervention delivered entirely over the phone via conference calls compared with a parallel clinic delivered in the traditional face-to-face manner. The primary outcomes were weight loss at 12 weeks and weight maintenance at 26 weeks. Attendance, meal replacements (MRs), fruits/vegetables (F/V), and PA were measured weekly for process evaluation.

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Methods

Participants

Twenty-four men and 72 women, ages 25–68 years, with a body mass index (BMI) of 33. 2plusminus3.8 volunteered for this 26-week RCT. Participants were healthy as judged by a written medical history, weight stable, not using tobacco products, and free from metabolic disease and medications known to alter metabolism (e.g. antidepressants, insulin, etc.). Participants on stable blood pressure medications were eligible to participate. Participants had to be able and willing to exercise (i.e. walk). All participants were given a detailed letter explaining the diet and PA, and were encouraged to share it with their personal physician. Participants were randomized to phone, clinic or control groups. As an incentive, participants randomized to the control group were enrolled in a weight loss clinic after 12 weeks, and thus only participants in the phone and clinic groups (main comparison) are included in the 26-week analysis.

Approval for the investigation was obtained from the Human Subjects Committee at The University of Kansas and Informed Consent was signed by each individual before any participation in this investigation.

Weight management clinics

Parallel weight management clinics were conducted weekly for 60 min for both phone and clinic groups. The phone group participated via a group conference call with the health educator and the clinic group attended a traditional face-to-face clinic with the health educator. Experienced health educators received standardized training and used identical lessons and materials (notebooks, handouts, etc.). Both phone and clinic groups received the same behaviorally based clinic on topics of lifestyle change, PA and nutrition. For example, topics included preparation of MRs, addition of F/V, PA, goal setting, self-monitoring, etc. At each meeting, participants in phone and clinic groups reported the number of MRs consumed, the number of F/V consumed and the calories expended each week through PA. The phone group gave a weekly self-reported weight and the clinic group weighed weekly on a scale at the clinic site. Phone participants received their MRs weekly through the mail, whereas clinic participants received MRs at the clinic site after each meeting. Participants were required to attend 75% of all meetings to remain in the study. Other than recruitment meetings, baseline, 12 and 26-week measurements, there was no face-to-face contact with the phone participants.

Weight loss diet

Energy intake was reduced to approx1200–1500 kcal/day using a combination of MR and F/V. A typical daily weight-loss diet can be found in Table 1. MR consisted of either formulated liquid shakes or entrees that were combined with other foods (Health Management Resources, Boston, MA, USA). Participants consumed a minimum daily total of three shakes at approx100 kcal each. The shakes were powdered individual servings that were mixed with approx8 oz of water. They were flavored as either chocolate or vanilla, and were taken cold or hot. The participants consumed daily two entrees that were between approx140 and 270 kcal each, and five servings of F/V (no dried fruit or juices). There were a variety (N=10) of entrees such as five bean casserole, chicken and rice, lasagna, beef stew, and turkey chili. Noncaloric beverages such as water, diet soda and coffee were allowed ad libitum. If participants reported hunger during the diet, they were encouraged to consume more F/V or MR.


Weight maintenance diet

Participants consumed a weight-maintenance diet with an energy level calculated to maintain weight loss. Participants used healthy eating strategies learned during phone or clinic group participation (i.e. portion control, diet records, high-volume/low-energy foods). Participants were encouraged to continue to use a minimum of 14 MR a week (two/day), five servings of F/V and noncaloric beverages of choice.

Physical activity

Moderately vigorous PA was targeted at a minimum of 2000 kcal/week using a progressive protocol of both structured exercise and lifestyle PA. Energy expenditure of PA was self-reported and was estimated from kilocalories per kilogram of body weight per minute for a variety of activities such as walking, swimming, gardening, etc.19 The targeted energy expenditure of 2000 kcal/week was achieved within the first 4 weeks by starting with a daily 15-min session and then adding an accumulation of approx10 more min/day each week for the next 3 weeks. The targeted energy expenditure was then held steady for the remainder of the study, although participants were encouraged to do more if they were capable.

Body weight

Weights for primary outcomes were recorded at baseline and 12 weeks for the phone group, clinic group and controls. Weights were recorded at 26 weeks for the phone and clinic groups. All weights were obtained with a calibrated digital scale (Befour Inc. Model #PS6600, Saukville, WI, USA) accurate to plusminus0.1 kg and participants were clothed in a standard hospital gown.

Quality of life/diet satisfaction and impact surveys

A modified version of the Diabetes Quality of Life Measure (DQOL) was used to describe how satisfied participants were with their diets and what impact the diet had on their lives (e.g. satisfaction with taste, interference with other activities, difficulty eating away from home, etc.). The DQOL20 has been shown to have high degrees of internal consistency for the satisfaction and impact subscales. Responses were based on a 5-point Likert scale from 1 (very satisfied/totally agree) to 5 (very dissatisfied/totally disagree).

Structured interviews

Participants completed structured interviews with trained staff using a script. Questions were designed to discover benefits and barriers regarding time commitments, impact on family, job, and lifestyle, travel, cost, convenience of attending meetings by phone or clinic, class dynamics (i.e. rapport, accountability, etc.) and overall satisfaction with the weight management program.

Statistical analysis

Weight change for completers was compared among all three groups at 12 weeks and between the phone and clinic groups at 26 weeks. The Kruskal–Wallis test was used to compare the change in weight at 12 weeks among the three groups. Since there was a significant difference among the three groups, pairwise comparisons were then conducted. The Wilxcoxon rank-sum test was used to compare the change in weight between the phone and clinic group at 26 weeks. Nonparametric tests were performed based on the moderate sample size in each group and the moderate degree of skewness in the distribution of weight change at each time point. This approach preserved the original units and measures of the data to facilitate clinical interpretation. Summary statistics for weight and BMI are given in terms of median and (range). All other process variables such as F/V, PA, and QOL are given as meanplusminuss.d.

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Results

Ninety-seven participants started the investigation and 74 completed 12 weeks (76%). Baseline characteristics of the participants are shown in Table 2. From baseline to 12 weeks, nine participants were terminated or withdrew from phone (26%), 12 from clinic (31%), and two from control groups (9%). Reasons for attrition included not meeting the attendance requirement (scheduling conflicts, transportation issues, etc.), noncompliance with the study protocol, dissatisfaction with the study condition, and the participant's perception they could continue successfully on their own. No additional participants were terminated or withdrew from 12 to 26 weeks.


For individuals who remained in treatment, participation at meetings from baseline to 12 weeks was 95 and 92% for phone and clinic groups, respectively. Participation at meetings from 12 to 26 weeks was 92 and 89% for phone and clinic groups, respectively. Participants in the phone group at 12 weeks reported consumption of 38.6plusminus4.2 MR and 44.6plusminus8.5 servings of F/V per week. Participants in the clinic group at 12 weeks reported consumption of 38.6plusminus4.1 MR and 42.0plusminus5.6 servings of F/V per week. Participants in the phone group at 26 weeks reported consumption of 35.0plusminus8.8 MR and 46.3plusminus10.9 servings of F/V per week. Participants in the clinic group at 26 weeks reported consumption of 20.6plusminus4.6 MR and 39.9plusminus4.9 servings of F/V per week.

Participants in the phone group reported 2134plusminus979 kcal of moderately vigorous PA compared with 2656plusminus970 kcal for the clinic group from baseline to 12 weeks. Participants in the phone group reported 2078plusminus622 kcal of moderately vigorous PA compared with 2837plusminus1271 kcal for the clinic group from week 12 to week 26.

Weight loss was measured from weights obtained at baseline and at the end of 12 and 26 weeks. Median weight loss at 12 weeks was significantly different between phone at 10.6 kg (16.6) or 10.4% and clinic at 12.7 kg (19.9) or 13.7%, and both were significantly different when compared with the control group that showed a median weight loss of 0.25 kg (5.6) or 0.24% (Figure 1).

Figure 1.
Figure 1 - Unfortunately we are unable to provide accessible alternative text for this. If you require assistance to access this image, please contact help@nature.com or the author

Body weight changes. Values are medians. *12-week weight change significantly different from control group (P<0.05). 12-week weight change significantly different between phone and clinic groups (P<0.05).

Full figure and legend (37K)

Median weight loss at 26 weeks was 12.8 kg (23.4) or 13.0% from baseline for the phone group and 12.5 kg (35.2) or 12.6% from baseline for the clinic group and were not significantly different (P>0.05). Likewise, changes in BMI for 12 weeks were significantly different between phone and clinic groups and both were significantly different from control (P<0.05). At 26 weeks, there was no significant difference between phone and clinic groups for BMI (P>0.05; Figure 2).

Figure 2.
Figure 2 - Unfortunately we are unable to provide accessible alternative text for this. If you require assistance to access this image, please contact help@nature.com or the author

BMI changes. Values are medians. *12-week BMI change significantly different from control group (P<0.05). 12-week BMI change significantly different between phone and clinic groups (P<0.05).

Full figure and legend (35K)

Table 3 shows the number of participants who achieved <10, 10–14.9, 15–19.9 and >20% weight loss from baseline at 12 and 26 weeks. Almost twice the clinic group compared with phone participants failed to achieve 10% weight loss at 12 and 26 weeks. The number of participants that achieved 10–14.9% weight loss was similar at both 12 and 26 weeks for phone and clinic groups. Approximately, twice the participants in the clinic group compared with the phone group lost 15–19.9% of baseline weight. No participant lost >20% of baseline weight at 12 weeks; however, three participants in the phone group and four in the clinic group achieved >20% weight loss at 26 weeks.


Participants of both groups reported a high degree of dietary satisfaction and overall well-being. Using the DQOL Likert scale (1=not satisfied; 5=very satisfied) there were no significant differences between the clinic group vs the phone group regarding the taste of the food (4.5plusminus0.6 vs 4.1plusminus0.9), the amount of food (4.3plusminus0.6 vs 4.1plusminus1.1), general life satisfaction (4.1plusminus0.6 vs 4.1plusminus0.7) and ability to manage weight (3.8plusminus1.0 vs 3.2plusminus1.2), respectively. The clinic group reported significantly greater levels of satisfaction with their nutrition knowledge over the phone group (4.5plusminus0.8 vs 4.0plusminus0.8) as well as the amount of time they spent exercising (4.0plusminus1.0 vs 2.7plusminus1.3), respectively. Both groups were asked questions at end study to assess satisfaction with the program and their group assignment. Using a reverse scale (1=totally agree; 5=totally disagree), both the clinic and phone participants said the program was easy to do (2.2plusminus1.5 vs 2.2plusminus1.2), that getting in contact with the group leader was easy (1.7plusminus1.5 vs 1.8plusminus1.2) and that the focus was on treatment during group discussions (1.9plusminus1.6 vs 2.0plusminus1.4), respectively (P>0.05).

To obtain additional feedback from participants, we conducted structured interviews following the conclusion of the investigation. Trained interviewers used scripts regarding benefits and barriers for the respective programs. All participants indicated general satisfaction with the phone and clinic methods and would participate again if needed. Phone participants indicated benefits for time savings for job, family, school, and child care commitments. One hundred percent of phone participants commented on the convenience and ease to participate in a conference call from anywhere including during periods of travel. Although we did not conduct a formal cost analysis, 80% of phone participants perceived cost reductions since travel was eliminated, whereas 70% of clinic participants expressed concerns about the time and cost for travel to the clinic. Ninety percent of phone participants indicated satisfaction with the group dynamics and rapport from fellow participants. Sixty percent indicated the phone gave them a mixture of accountability and privacy (anonymity), and decreased potential embarrassment of sharing thoughts and feelings that may occur in face-to-face meetings. Interestingly, 70% of clinic participants indicated they would like to participate in a weight maintenance class by phone as this would allow them to keep the accountability that a clinic provides but they would not have to travel and this would reduce costs (Table 4).


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Discussion

This RCT was designed to compare a phone-delivered weight management clinic to the traditional face-to-face clinic. Both approaches used the same behaviorally based program that emphasized nutrition, PA and lifestyle changes. We were interested to determine if the phone approach would provide similar results to the clinic approach and if the percentage of weight loss and maintenance would reach the NHLBI guideline of 10% reduction from baseline weight.

Attrition at 12 weeks for the phone group (26%) was less than that shown for the clinic group (31%) and both were greater than that shown for the control group (9%), and this may reflect the relative burden for the respective participants. There was no further attrition for either phone or clinic groups from 12 to 26 weeks and this may reflect assimilation and satisfaction of the participants with their respective programs since comments from structured interviews were quite positive. Attendance at the meetings was good for both groups with phone attending 94% and clinic attending 90% of all scheduled meetings.

Compliance with the diet for both phone and clinic groups exceeded the targeted amount of MR and F/V at both 12 and 26 weeks of the diet. During maintenance, the phone group reported consumption of a greater amount of MR and F/V compared with the clinic group. Since reported consumption of MR by the phone group equaled or exceeded those reported by the clinic group, it appears that the phone was as effective as the clinic to encourage consumption of MR and F/V, and that delivery of diet products by land transportation is as effective as obtaining products at clinic meetings.

Estimated energy expenditure of PA exceeded the target of 2000 kcal/week for both diet and maintenance. Numerous investigations have previously shown that PA is one of the best predictors of weight maintenance21 and it is likely that the high level of PA contributed to weight maintenance above 10% from baseline weight in this investigation.

The primary outcomes for this investigation were the comparisons between phone and clinic groups for weight loss and maintenance at 12 and 26 weeks. The median weight losses were significantly greater for the clinic group at 12 weeks, but not at 26 weeks. This is encouraging for the phone approach, since weight loss is achieved by many but weight maintenance by few.22, 23 The phone and clinic groups showed median weight loss that exceeded 10% at 12 and 26 weeks, thus meeting the NHLBI guidelines. A recent review has shown MR to generally exceed conventional diets for weight loss and this is reflected in the current investigation.24 Thus, it may be suggested that MR are emerging as a state-of-the-art strategy for weight loss and maintenance. MR may be used for long periods or indefinite periods since they are 'real meals' that are simply prepackaged. MRs offer energy and portion control and generally have a reduced fat content. Additionally, many MR are shelf stable, may be transported between sites such as home and work and are easily prepared in a short time period. Importantly, there were no reported adverse events associated with the use of MR for either phone or clinic groups.

We targeted 10% weight loss from baseline because this is the current recommendation of NHLBI and this amount of weight loss shows improvements in chronic disease risk factors.2 Although median weight loss exceeded the 10% recommendation at both 12 and 26 weeks, there was considerable variation between groups (Table 3). The most noticeable difference is that the phone group had approximately twice the number of participants who did not achieve 10% weight loss. We are uncertain regarding what may be responsible for this outcome since the phone group was as compliant to the meetings, diet and PA compared with the clinic group. Interestingly, the number of participants achieving >20% weight loss was similar between phone groups and clinic groups at 26 weeks and may indicate the potential benefits of the phone-based approach as the duration of weight management increases.

The results from the structured interviews were encouraging for the use of phone interventions for weight management. A number of advantages compared to clinic were discovered including convenience, time savings, diminished impact on family, job and lifestyle, diminished estimated costs for travel, and satisfaction with group dynamics including a balance of accountability and anonymity. All phone participants indicated convenience of participating in phone meetings from any location and this may partially explain the improved attrition rate of the phone group compared to the clinic group.

This investigation has some limitations worth mentioning. As with the majority of clinical trials for weight management, men are under represented as they do not seem to present for weight management at the rate of women. MRs, PA, and F/V consumption, were self-reported and may be subject to over or under estimation. Although we provided some analysis of potential differences for costs associated with the phone and clinic delivery systems, we acknowledge that a more formal and thorough cost analysis is warranted.

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Conclusions

We have shown that a phone-based approach to weight management provides weight loss that is not different compared with traditional, state-of-the-art, face-to-face, behavioral weight management clinics and that weight loss and weight maintenance exceeded NHLBI guidelines. We have shown it is possible to engage individuals in weight loss and weight maintenance using the phone approach and provide a behaviorally based program and diet-related products using ground transportation. Attrition was less and attendance was greater in the phone group compared with the traditional clinic group, and this may reflect diminished barriers and burdens for participation. Other than baseline, 12 and 26-week measures, the phone participants were sight unseen. When translated into clinical practice, it may be possible to engage individuals in effective weight loss and weight maintenance programs regardless of location or access to transportation without any face-to-face encounters. Since maintenance of weight loss is the ultimate goal for weight management, the utility of phone-based interventions should be pursued in long-term investigations.

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Acknowledgements

This work was supported in part by Health Management Resources, Boston, MA.

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