In this study, we report lifestyle habits that were associated with weight regain in a group of primary care patients enrolled in the MAINTAIN-pc trial over 24 months. The three habits most consistently associated with weight regain (at both 6 and 24 months) were increased eating at restaurants, decreased fish consumption, and decreased physical activity. Increased sedentary behavior was associated with weight regain at 6 months and decreased low-fat foods and increased in sugary beverages and desserts were associated with weight regain at 24 months. Taken together, we summarize the key habits associated with weight regain among MAINTAIN-pc participants that could be useful behavioral targets for primary care providers and their patients seeking to maintain recent weight loss success (Table 4).
Measurable health and quality of life benefits are realized with weight losses of 5–10%, and these are sustained if weight lost is not regained.5,7 Thus, long-term weight loss maintenance is the treatment goal for obesity. With further consideration that the 1- to 5-year period following initial weight loss is when most weight is regained,5,6 a focus on strategies to maintain weight loss in the first few years is key. Moreover, some studies suggest initial weight loss vs. weight loss maintenance behavioral strategies might differ.8 This concept is reinforced when synthesizing findings of this current weight regain analysis with our previous research associating lifestyle habits with recent intentional weight loss in MAINTAIN-pc.15 Though physical activity associated with both recent weight loss and reduced weight regain, greater fruits, vegetables, and low-fat foods were most associated with recent weight loss15 while greater fish consumption and less eating at restaurants were most consistently associated with reduced weight regain.
Varkevisser and colleagues recently systematically reviewed 124 demographic, behavioral, psychological, and environmental factors associated with weight loss maintenance.13 Specifically for the factors most consistently associated with reduced weight regain in our study, this review graded the evidence as “strong” for reduced restaurant eating and higher physical activity and “moderate” for increased fish consumption. The evidence for other behavioral factors that we identified as potentially important for attenuating weight regain were graded as “strong” (less sugary beverages) or “insufficient” (desserts, sitting time; more low-fat foods or recipes). Of interest for the habits that we found were not associated with weight regain in multivariable models, this review graded the evidence that fruit and vegetable intake was associated with less weight regain as “strong” while fried food intake was graded as “insufficient”.13
Several large survey or observational cohorts have investigated lifestyle habits associated with weight regain. In an analysis from the National Weight Control Registry (N = 2886), a survey study that remotely enrolled volunteers who self-reported weight losses of ≥ 30 lbs. that had been maintained for ≥ 1 year, participants who decreased physical activity and increased dietary fat intake were more likely to regain weight lost over 10 years.9 Though consistent with our findings regarding physical activity and low-fat foods, our findings among MAINTAIN-pc participants recruited through primary care offices, and often with more recent (within last 2 years) and modest (≥ 5%) weight losses, could be more translatable when treating patients during the most vulnerable period for weight regain. Another survey8 conducted on a random sample of 1165 US adults identified several lifestyle habits associated with weight loss maintenance that were consistent with our study, including higher consumption of low-fat proteins (potentially comparable with our fish intake) and consistent engagement in exercise. In contrast to our findings, this survey study additionally identified higher consumption of fruits and vegetables as a weight loss maintenance strategy. In the Coronary Artery Risk Development (CARDIA) observational cohort,10 lifestyle habits associated with weight loss maintenance in mid-life among 534 participants included increasing physical activity and decreased sugar-sweetened beverages, though changes in overall Healthy Eating Index were not associated. Taken together, higher participation in physical activity appears to be most consistently associated with weight regain, while dietary habits are more variable.
Like this current study, habits associated with weight regain have also been evaluated within clinical trials. In the Weight Loss Maintenance (WLM) trial,12 participants (n = 1685) losing at least 4 kg during an initial 6-month intensive phase were randomized to three interventions for weight loss maintenance. Lifestyle habits associated with maintaining weight lost in the WLM included increases in the Healthy Eating Index and moderate-vigorous physical activity.12 Among participants (n = 105) recruited from primary care offices in Poland in a diabetes prevention lifestyle intervention study,11 only decreased fat consumption predicted weight loss maintenance at 3 years; changes in physical activity, fruit and vegetable intake, saturated vs. unsaturated fat intake, and alcohol consumption were not related. However, compared with these studies, our data may be more relevant to a typical, clinical population. Our participants had achieved weight loss through a variety of self-guided behavioral methods (rather than as part of an initial trial), our study assessed specific dietary habits (e.g., restaurant eating, fish consumption), and we included objective assessment physical activity.
Overall, despite differences in study populations and the exact habits evaluated, our results are largely consistent with the previous literature13 and, moreover, conventional wisdom that advocates an active lifestyle and eating meals at home that include fish, are low in fat, and have limited added sugars. Of note, greater intake of fish in this study may reflect the recommended dietary pattern that replaces less healthy proteins with leaner, healthier proteins24; we were unable to assess other proteins separately with the dietary questionnaire used. That fruit and vegetable intake was not consistently protective of weight regain in the multiply adjusted models is our most unexpected result.10,25 One possibility is that increases in the consumption of fruits and vegetables during the weight loss maintenance phase could reflect an overall increase in dietary intake rather than a less calorically dense dietary pattern that may have contributed to initial weight loss.15,26
Our study has several limitations. Lifestyle variables (dietary habits, moderate-vigorous physical activity, and sedentary behavior) are self-reported and may have been subject to recall or social desirability biases. We were limited in dietary habits and other data that we could extract from the Diet Habit Survey; for example, total caloric intake, consumption of lean proteins, or method of fish preparation were not available. Our evaluation of lifestyle behaviors without accounting for total caloric intake, physiological factors, or chronic conditions could have impacted associations. Also, the study was powered to detect a weight change between two randomized groups and may have had limited power to detect smaller associations in this secondary analysis that combined randomized groups. Thus, caution should be used when interpreting these hypothesis-generating associations that do not reflect an experimental test of the effect of altering these specific habits. Though we did not adjust the family-wise error rate for the multiple habits considered within each model, consideration of 10 habits could have inflated type I error. Lastly, as is typical in weight interventions, the population in MAINTAIN-pc was mostly female, white, and educated, which reduces generalizability. These limitations are balanced by strengths, which include prospectively assessed changes in habits that readily translate into potential strategies within a relevant, contemporary cohort of primary care patients, with a high prevalence of comorbidities, and who achieved intentional weight loss through a variety of behavioral methods.
The findings of this study could be useful for primary care practice. Despite the 2018 US Preventative Task Force recommendation to offer or refer adults with obesity to behavior-based weight loss maintenance interventions (moderate certainty, grade B),27 weight control counseling in primary care remains underutilized.28 Numerous barriers to such counseling include high workload, lack of patient interest, or lack of training or referral resources.28,29 Our data suggest referring patients with recent, intentional weight loss to coaching helps them stay committed to their weight-controlling behaviors. Staying active; sustaining or increasing dietary behaviors such as consumption of fish and low-fat foods; and maintaining or reducing eating at restaurants, sugary beverages, and desserts may all help prevent weight regain. Though beyond the scope of this manuscript, providers could consider counseling through methods including shared decision-making or motivational interviewing to patients with recent intentional weight loss, or referral to behavioral specialists.30 Future research could evaluate whether counseling from members of the primary care team (e.g., providers, staff) that focuses on behavioral strategies to maintain physical activity and dietary habits could reduce weight regain with the ultimate goal of improving obesity treatment outcomes.