Maintenance of Weight Loss After Initiation of Nutrition Training: A Randomized Trial

Abstract

Background: Weight regain after successful weight loss interventions is common.

Objective: To establish the efficacy of a weight loss maintenance program compared with usual care in obese adults.

Design: 2-group, parallel, randomized trial stratified by initial weight loss (<10 kg vs. ≥10 kg), conducted from 20 August 2012 to 18 December 2015. Outcome assessors were blinded to treatment assignment. (ClinicalTrials.gov: NCT01357551).

Setting: 3 primary care clinics at the Veterans Affairs Medical Center in Durham and Raleigh, North Carolina.

Patients: Obese outpatients (body mass index ≥30 kg/m2) who lost 4 kg or more of body weight during a 16-week, group-based weight loss program.

Intervention: The maintenance intervention, delivered primarily by telephone, addressed satisfaction with outcomes, relapse-prevention planning, self-monitoring, and social support. Usual care involved no contact except for study measurements.

Measurements: Primary outcome was mean weight regain at week 56. Secondary outcomes included self-reported caloric intake, walking, and moderate physical activity.

Results: Of 504 patients in the initial program, 222 lost at least 4 kg of body weight and were randomly assigned to maintenance (n = 110) or usual care (n = 112). Retention was 85%. Most patients were middle-aged white men. Mean weight loss during initiation was 7.2 kg (SD, 3.1); mean weight at randomization was 103.6 kg (SD, 20.4). Estimated mean weight regain was statistically significantly lower in the intervention (0.75 kg) than the usual care (2.36 kg) group (estimated mean difference, 1.60 kg [95% CI, 0.07 to 3.13 kg]; P = 0.040). No statistically significant differences in secondary outcomes were seen at 56 weeks. No adverse events directly attributable to the intervention were observed.

Limitations: Results may not generalize to other settings or populations. Dietary intake and physical activity were self-reported. Duration was limited to 56 weeks.

Conclusion: An intervention focused on maintenance-specific strategies and delivered in a resource-conserving way modestly slowed the rate of weight regain in obese adults.

Primary funding source: Veterans Affairs Health Services Research and Development Service.

Figure 1

MAINTAIN study phase 2 patient flow (weight loss maintenance). MAINTAIN = Maintenance After Initiation of Nutrition Training. Detailed inclusion and exclusion criteria for phase 2 (randomized clinical trial) of the MAINTAIN study are described in the Methods section and the Appendix Figure (available at Annals.org). In brief, patients included in the study were aged 18 to 75 years with a body mass index ≥30 kg/m². Patients whose weight could or should not be measured with a bioelectric impedance scale and women who were pregnant or breastfeeding were excluded. In addition, patients with a history of any of the following were excluded: kidney or liver disease, type 1 diabetes, elevated systolic blood pressure, surgical or recent behavioral or pharmaceutical weight loss attempts, mental health or substance abuse issues, recently treated heart disease, cancer not in remission, or receipt of an organ transplant.

Figure 2

Model-estimated weights, differences in weights, and associated 95% CIs, by treatment group and week. Bars are 95% CIs. Weight estimates for each time point were calculated by using a general linear model with an unstructured covariance to account for the correlation of patients’ repeated measurements over time. Model parameters included a common intercept (which constrained the baseline means to be equal); initial weight loss stratum (centered); indicator variables for weeks 14, 26, 42, and 56; and indicators for the maintenance intervention interacted with each follow-up time point indicator variable. Contrast statements were used to estimate the difference between the groups in weight regain from week 0 to each of the 4 follow-up time points. The model-estimated weight correlation between time points ranged from 0.99 (weeks 0 and 14) to 0.97 (weeks 0 and 56). NA = not applicable (because the model constrained the baseline means to be equal).

Appendix Figure

MAINTAIN study phase 1 patient flow (weight loss initiation). BMI = body mass index; MAINTAIN = Maintenance After Initiation of Nutrition Training. * Exclusion criteria determined by data pull included most recent serum creatinine value >2.0 mg/dL in men or >1.7 mg/dL in women; liver disease; type 1 diabetes; most recent hemoglobin A_1c value in the past 6 mo ≥12%; average systolic blood pressure over the past year ≥160 mm Hg and most recent blood pressure reading ≥160 mm Hg; and history of weight loss surgery, dementia, severe psychiatric illness, or substance abuse. † 10 807 patients were mailed letters; 38 were mailed letters as well as being self-referred; 239 were self-referred, with no letter sent. ‡ Obtained by subtraction. § Potential reasons for ineligibility assessed by telephone included BMI ≥29 kg/m² based on self-reported weight and height (reduced threshold to allow for error in reporting); self-reported age <18 or >75 y; weight loss ≥10 lb in the previous 3 mo; current enrollment in a lifestyle program; history of weight loss surgery; current use of weight loss medication or appetite suppressant; pregnancy or plan to become pregnant in upcoming 6 mo, breastfeeding, or lack of birth control if premenopausal (female); organ transplant recipient; type 1 diabetes; heart disease with new treatment in past 3 mo; liver disease; cancer not in remission; pacemaker or defibrillator (because of the use of a bioelectronic impedance scale); major depression or emotional problems that would prevent the participant from following a diet closely or interacting with others in a group environment; illicit drug use or alcohol problems in the past year; inability to stand for study measurements; lack of desire to lose weight; lack of agreement to attend study visits; and no access to telephone or reliable transportation. || Two of the 267 patients ineligible at phone screen (1 because of BMI and 1 because of age) are included in both the “Scheduled for in-person consent and screening” and “In-person consent and screening” boxes. One was ineligible at phone screen because of BMI <30 kg/m² but then was erroneously rescreened in person and excluded at that point for the same reason. The other patient was listed as excluded because of age >75 y at both phone and in-person screen. Both exclusions were erroneous because the patient was aged 75 y at both time points; however, the patient was not included in the study after the in-person screen.