To our knowledge, this is the first study to examine weight change in association with changes in three vital behaviors for weight loss—food journaling, recording of days/week of physical activity, and session attendance—at six and eighteen months. Our findings offer a unique perspective on how adherence to these practices correlates to five specific weight change patterns. Even though there were differing patterns of weight change, the frequency of all three behaviors between six and eighteen months decreased for all participants. However, those participants who maintained weight loss averaged smaller percentage changes in the number of food journals, recorded days/week of physical activity, and attendance rates than those who gained weight or lost weight but subsequently relapsed. Those who were weight stable or had late weight loss had significantly less decline in their attendance rate compared to those who gained or lost weight but subsequently relapsed. This suggests that the degree of change in key behaviors may have significant influence on weight change patterns in the long term.
Overall our results are encouraging with regard to the amount of effort patients might need to expend to achieve and maintain successful weight loss. A significant number of patients achieved a 5% weight loss with a relatively low number of days per week of recorded physical activity and dietary intake, and incrementally small increases in frequency were associated with even greater odds of losing 5%. In some instances, smaller goals may be viewed as more achievable by patients, thus increasing both willingness and self-efficacy, increasing the chances for successful behavior change25–26
. Clinicians may also find themselves more comfortable and confident in their ability to counsel and motivate patients towards behavior change using these modest targets, particularly given that time constraints and futility are commonly cited as barriers to weight loss counseling in daily practice27–28
Of all of the declines in behaviors, it was of significant interest to see that weight loss was achieved and maintained with lower levels of self-reported physical activity than previously observed in other studies7,18–20
. For those attempting to maintain weight loss, the most recent 2008 Physical Activity Guidelines for Americans recommends 60 minutes of moderate or 30 minutes of vigorous physical activity daily 29
. The average of approximately two days per week of reported activity for weight loss maintainers in this study is well below the recommendation, yet they still achieved long term weight loss. It may be important to consider the context for this intervention when interpreting these results. Despite the decline in physical activity over time, it appears that maintenance of weight loss may be achieved with lower levels of physical activity when patients consistently practice self-monitoring of dietary intake and attend a structured group behavioral program.
In addition, our findings showed that the frequency of food journaling, recording physical activity, and attendance to group sessions at 18 months more strongly impacts long term weight change than the same frequency at six months. For example, a person recording physical activity 1–2.9 days per week has a 4 times higher odds of losing at least 5% of his or her baseline weight at six months, but a 7-fold increase in odds of losing 5% of baseline weight at 18 months. If adherence to key behaviors will most likely wane over time as seen in this study, we speculate that it may be more effective to offer aggressive counseling and interventions to reinforce adherence after the first six months of a weight loss endeavor. This is especially important because participants were on average gaining weight in the last 12 months of this intervention. This is consistent with other studies that have shown an average regain of 30–35% of weight loss during the year following treatment cessation30–31
. In this study, only participants who were in the highest categories for food records, recorded days/week of physical activity, and attendance at behavioral sessions experienced weight loss in the second phase of the study. Given previous findings regarding rates of weight regain over the long term32–34
, this does not come as a surprise, but rather supports the idea that over the long term, the focus should switch to prevention of weight regain and helping individuals maintain a significant level of adherence to key behaviors.
This study is not without limitations. First, physical activity was measured by participants’ self-report, which is often overestimated. However, to a large extent, self-report remains the most common way to gauge patients’ physical activity level in current clinical practice, which enhances the generalizability and applicability of our findings. Second, this study assessed the relationship between the observed behaviors and the weight change patterns; as a result, it does not imply cause and effect. While we described associations of clinically meaningful weight loss with fewer than recommended days of journaling (i.e., daily), further research is needed to determine if people randomized to differing prescriptions for journaling of physical activity and dietary intake lead to different weight change outcomes. Additionally, it will be important for future research to determine if increases or even prevention of decreases in the behaviors of self-monitoring dietary intake and physical activity along with group attendance can lead to additional weight loss at later stages (i.e., beyond the acute weight loss stage) in behavioral intervention programs. The early adoption of these behaviors may not translate into late maintenance of these behaviors for many people, potentially creating opportunities to intervene when the potential for recidivism is high. The third limitation relates to the smaller sizes of subgroups that were created based on the weight change cut points. The findings related to the groups that gained or had late weight loss may not be as generalizable as those related to the other groups.
In conclusion, our study illustrates how the frequency of three key behaviors associated with weight loss including food journaling, physical activity, and attendance at behavioral counseling sessions, are associated with weight change over both the short and long term among overweight and obese individuals. We determined that despite an overall decline in frequency of each behavior over time and a relatively infrequent average occurrence of each behavior at 18 months, the majority of participants maintained weight loss and/or prevented weight gain. In addition, our study implies that the change in behavior frequency over a particular time period may be more predictive of weight change patterns than the average behavior frequency at any single time point. Our study also suggests that a relatively small increase in any one behavior can generate a substantial increase in the odds of achieving a 5% decrease in weight. Combined, these findings offer practical and applicable considerations for weight loss counseling, particularly with regard to goal setting and long-term weight loss strategies. Small but consistent steps may be the best route to successful long term weight maintenance.