Go BIG! Recommending Large Behavior Changes to Prevent Weight Gain

We’re all aware that there is an obesity epidemic and its linked to dozens of health problems.¹  But nothing we’ve done so far — public awareness campaigns, changes in school lunch programs, and approving new drugs for weight loss — has halted this epidemic.  Although the rate of obesity in kids age 2 to 19 has plateaued around 17%, it continues to climb in young adults and most of us keep packing on the pounds as we get older!²

For patients with obesity, weight loss from lifestyle changes alone can be challenging. While we have more than 100 hundred medications for obesity-related co-morbidities (diabetes, hypertension, cholesterol), we have only six medications FDA-approved for the long-term treatment of obesity.  We clearly need more data regarding environmental and behavioral drivers that help us maintain a healthy weight  …  including interventions that are scalable and sustainable.  Few studies to date have focused on obesity prevention. Although many short-term weight management studies have been conducted, mixed results have made it difficult to determine which intervention(s) lead to the greatest weight loss.  Moreover,  few studies have implemented interventions for longer than 18 months.³  The recently published Study of Novel Approaches to Weight Gain Prevention (SNAP) provides important long-term evidence regarding weight loss prevention in young adults.

The SNAP study was a randomized clinical trial designed to compare two self-regulated interventions (small-changes and large-changes) versus control to prevent weight gain among young adults. The primary aim of the study was to determine the mean weight change over a  3-year follow up period. The secondary aim of the study was to measure the number of participants gaining 0.45kg (1 lb) or more and the incidence of obesity over the 3 years.

A total of 599 participants, ages 18 to 35 years with body mass indexes between 21.0 and 30.9, were recruited and randomized to one of the three study arms.  Particular attention was paid to achieving a sample with at least 25% male participants and 25% racial and ethnic minorities.

The interventions were based on a self-regulation model using a negative feedback loop.  The subjects were given a goal (not to exceed their baseline weight), instructed to measure their progress toward the goal (daily self-weighing), and told to take action (diet and exercise) to achieve the goal.  Subjects in the control group participated in a single face-to-face meeting where they learned about self-regulation, and how both small- and large-change approaches can potentially minimize weight gain. In the small-change group, participants were encouraged to make small daily changes to create a small calorie deficit (100 calories/day) through diet and exercise.  In the large-change group, participants were asked to lose 2.3 kg (5 lbs) if normal weight or 4.5 kg (10 lbs) if overweight in the first 4 months of the study.  This initial weight loss was intended as a buffer against future weight gain.  Large-changes participants were asked to achieve this by making large changes to diet (500-1000 calorie deficit/day) and exercise (250 minutes of moderate-intensity activity/week). Participants in the two intervention groups attended 10 face-to-face meetings over the first 4-months (weekly for 2 months, then monthly for 2 months). Participants in the intervention arms of the study also had the option to participate in two 4-week online refresher courses each year.

Daily weigh-in results were posted online via the study website, text message, or email. Participants received monthly color coded feedback which reinforced success or recommend additional strategies for weight loss. The recommended strategies were consistent with the participant’s group assignments and included making small additional changes or reducing the calorie goal and increasing the activity goal.

After 3 years of follow-up, participants in the control group had a mean weight gain of 0.26 (+/- 0.22) kg while the small-changes group had a modest mean weight loss of -0.56 (+/- 0.22) kg.  The large-changes group achieved a mean -2.37 (+/-0.22) kg weight loss. There were statistically significant differences between the small-change (p = 0.02) and large-change (p <0.001) groups relative to the control group as well the large-change group relative to the small-change group (p < 0.001). Weight gain of 0.45 kg or more was less common in the large-change group (23.6%) versus either the small-change (32.5%; p = 0.02) or control (40.8%; p < 0.001) groups. None of the pre-specified sub-groups (based on sex, age, and baseline weight) were found to have a significant effect on weight change.

This well designed trial has several strengths — a low attrition rate, long-term follow-up (far longer than previous trials), fidelity assessments to assure adherence with the study protocol (which were high), and the collection of multiple process measures such as changes in caloric intake, self-weighing, and levels of physical activity.⁴  However, despite efforts to ensure at least 25% of the sample was male, a majority of the participants were women. Additionally, there were small percentages of African Americans and Hispanics in the trial. Admittedly recruiting minorities into clinical trials can be difficult but efforts to increase the overall percentage of participants from these groups is important because they are disproportionately impacted by obesity when compared to whites.⁵ Also, the majority of the trial participants were well educated having graduated or attended college. Given that the obesity epidemic may be greater among individuals with lower educational attainment, the methods used in this study might not be feasible in all patient populations.

A few other studies have examined weight gain prevention. The Women’s Healthy Lifestyle Project aimed to prevent weight gain among perimenopausal and post-menopausal women.  Women in this study were asked to decrease caloric and fat intake and increase physical activity with the aim  of preventing the rise in LDL cholesterol seen following menpause.⁶ The Pounds of Prevention trial examined whether weight gain with age could be prevented using low-intensity interventions, such as education through monthly newsletters and participation incentives.⁷ The SHAPE program — a study conducted in overweight premenopausal Black female patients in a rural primary care setting — assessed a weight gain prevention intervention, consisting of tailored behavior change goals, self-monitoring, skills training, counseling calls with a registered dietitian, and a 12-month YMCA membership, for.⁸  The interventions in these studies were low-intensity and weight loss was not the goal.  The SNAP trial provides evidence that “large change” recommendations may provide the greatest benefit for weight gain prevention in young adults aged 18 to 35 years old.  The conventional wisdom has been to recommend small, incremental behaviorial changes.  The results of this study may influence how providers view and recommend weight gain prevention and weight management strategies.

Should obesity prevention be a covered benefit offered for normal weight, healthy, younger adults?⁹  The SNAP study clearly provides evidence that intensive patient education and ongoing monitoring can prevent weight gain.  Perhaps the old saying is true — an ounce of prevention is worth a pound of cure!

Given they are among the most trusted and accessible healthcare professionals, pharmacists are ideally positioned to managed weight gain prevention programs. Pharmacists can help patients acheive behaviorial change using methods similar to those implemented in the SNAP trial. These interventions lead to measurable outcomes and illustrate the impact pharmacists can have on patient care.  Future research should examine how pharmacists can be integrated into obesity prevention and management. 

What do you think? Should we abandon “small incremental changes” and, instead, recommend “large changes” in behavior to prevent (or treat) obesity?