In a small sample of mid-life, low-income women who completed a trial of a 16-week weight loss intervention followed by a 12-month maintenance program with monthly contacts, 18% succeeded in maintaining what would be considered clinically meaningful weight loss . Our study results, though not compared to outcomes in a control group, are comparable to success rates of 20% observed in previous research of 1-year weight loss maintenance after intentional weight loss . In a recent 2.5-year weight loss maintenance trial (WLM) , 42% of participants receiving monthly personal contacts (phone and face-to-face) maintained weight losses of at least 5% of initial weight, while 36% were within < 3% of their maintenance program start weight . While we observed a similar rate of 41-43% (for both definitions of maintenance), our study duration was much shorter. Our 12-month weight regain of 2.5 kg overall is, however, similar to the approximately 2 kg regain observed in the WLM personal contact group at 12-months of maintenance . Compared to the average regain of one-third of lost weight within 1-year of treatment , our overall weight regain of 38% is comparable, given our sample of high risk participants.
A recent review of randomized clinical trials of weight loss maintenance , showed effect sizes ranging from 0.01 to 0.30 for differences between treatment and control groups, in studies without medication treatment. Even though this pilot study did not include a control group, if program outcomes are compared, the observed differences in total weight regain translate into an effect size of 0.23. This pilot, like many of the weight loss maintenance trials in the review by Turk and colleagues , was underpowered to detect a difference in treatment effect.
With so few published weight loss maintenance studies among low-income women, it was difficult to find any comparable studies. One weight loss maintenance program for low-income minority women evaluated in a primary care setting  provided some data for comparison. In this study by Martin and colleagues, the difference between the treatment group and usual care (one year after a 6-month weight loss intervention) was a mean (SD) weight loss of -0.49 kg (3.3) in the treatment group and a weight gain of 0.07 (3.75) in usual care (with an effect size of 0.07). Additionally, only 7% of the maintenance intervention group had a weight loss of ≥ 5% of initial body weight at the 1-year end point . This was, however, a very low-dose intervention delivered in a different setting from our pilot program, thus making it difficult to directly compare outcomes.
We pilot tested two differently formatted maintenance programs and found that they appear to be similarly effective, even though the Face-to-Face + Phone program had about half the intervention dose (up to 11 hours of planned contacts) compared to the Face-to-Face Only program (20 hours total). There was over a 2 kg difference in total weight regain between programs, suggesting that the Face-to-Face + Phone program may have produced better maintenance outcomes. Statistical significance was likely affected by the small sample size. With strong evidence that some type of weight loss maintenance treatment is needed to prevent weight regain after intentional weight loss [12, 16], the next step is to identify cost-effective program options. Even though we did not evaluate the cost of our pilot programs, interventions delivered by phone generally cost less than face-to-face contacts (both in terms of program costs and costs to the participants [10, 12]. Combining phone and face-to-face group contacts brings together the cost advantages of phone-delivery and the benefits of group interactions (and enhanced social support), which seem to be important in interventions among low-income and minority populations. Probably the best evidence of effective long-term weight loss maintenance comes from the research of Perri and colleagues , where weight regained during a 1-year maintenance program was 1.2 kg in both the telephone-delivered and face-to-face formats. Some of the key features of this maintenance intervention include biweekly instead of monthly contacts, use of a problem-solving approach, and emphasis on self-monitoring. Translating this evidence to fit the needs of low-income women is an important next step in weight loss maintenance research.
Beyond the weight outcomes observed in this pilot study, implementing these programs gives us important information about feasibility and acceptability. In both programs attendance was good (nearly 80% overall), and program acceptability high. More importantly, improvements in cardiovascular risk factors (e.g., blood pressure and self-reported dietary changes in both groups and HDL cholesterol in Face-to-Face + Phone only) remained significant (within groups) at the end of the maintenance period. These sustained improvements in blood pressure even with some relapse in weight loss maintenance, are consistent with the findings from previous trials where short-term weight loss, even if not fully maintained, was protective relative to hypertension, in the longer-term [24, 25].
Even though we successfully implemented 2 weight loss maintenance interventions in a small sample of low-income midlife women, this pilot study has limitations that should be mentioned. Our pilot data are limited not only by the lack of a control group, but also by the small sample, and exclusion of men (which limits generalizability). Also, our two maintenance interventions were implemented at different time periods and may be subject to differential secular trends. Despite these limitations, this pilot study among a population group that is seldom studied, but at high risk for the negative consequences of obesity, shows promising outcomes in its high participant retention, intervention receipt and acceptability, and maintenance effectiveness.