By Catherine Lombard, Cheryce Harrison, Samantha Kozica, Sophia Zoungas, Sanjeeva Ranasinha, and Helena Teede

 

Abstract

Background

Obesity is reaching epidemic proportions in both developed and developing countries. Even modest weight gain increases the risk for chronic illness, yet evidence-based interventions to prevent weight gain are rare. This trial will determine if a simple low-intensity intervention can prevent weight gain in women compared to general health information.

Methods and Findings

We conducted a 1-yr pragmatic, cluster randomised controlled trial in 41 Australian towns (clusters) randomised using a computer-generated randomisation list for intervention (n = 21) or control (n = 20). Women aged 18 to 50 yr were recruited from the general population to receive a 1-yr self-management lifestyle intervention (HeLP-her) consisting of one group session, monthly SMS text messages, one phone coaching session, and a program manual, or to a control group receiving one general women’s health education session. From October 2012 to April 2014 we studied 649 women, mean age 39.6 yr (+/− SD 6.7) and BMI of 28.8 kg/m2 (+/− SD 6.9) with the primary outcome weight change between groups at 1 yr. The mean change in the control was +0.44 kg (95% CI −0.09 to 0.97) and in the intervention group −0.48kg (95% CI −0.99 to 0.03) with an unadjusted between group difference of −0.92 kg (95% CI −1.67 to −0.16) or −0.87 kg (95% CI −1.62 to −0.13) adjusted for baseline values and clustering. Secondary outcomes included improved diet quality and greater self-management behaviours. The intervention appeared to be equally efficacious across all age, BMI, income, and education subgroups. Loss to follow-up included 23.8% in the intervention group and 21.8% in the control group and was within the anticipated range. Limitations include lack of sensitive tools to measure the small changes to energy intake and physical activity. Those who gained weight may have been less inclined to return for 1 yr weight measures.

Conclusions

A low intensity lifestyle program can prevent the persistent weight gain observed in women. Key features included community integration, nonprescriptive simple health messages, small changes to behaviour, low participant burden, self-weighing, and delivery including a mix of group, phone, and SMS text reminders. The findings support population strategies to halt the rise in obesity prevalence.

Editors’ Summary

Background

Obesity—having an unhealthy amount of body fat—is a global public health problem. In the US, for example, more than one-third of adults are obese and another third are overweight. Obesity is defined as having a body mass index (BMI; an indicator of body fat calculated by dividing a person’s weight in kilograms by their height in meters squared) of equal to or more than 30 kg/m2; overweight individuals have a BMI of 25.0–29.9 kg/m2. Increased body fat is associated with an increased risk of developing diabetes, cancer, cardiovascular disease and other chronic diseases.. People gain body fat by consuming food and drink that contains more energy (calories) than they need for their daily activities. So excess body fat can be prevented and reversed by eating a diet that contains fewer calories and by being more active.

Why Was This Study Done?

BMI increases with age in most adults although in recent years young adults have been shown to be gaining body fat faster than older adults. However, the adult weight gain per year is generally less than 1 kg and could be prevented by encouraging people to eat just a little less and exercise just a little more. Prevention of weight gain is likely to be easier than reversal of established obesity, but few interventions designed to prevent weight gain have been rigorously tested. In this pragmatic randomized controlled trial, the researchers investigate whether a simple low-intensity intervention can prevent weight gain among 18–50-year-old women living in rural communities in Australia. Rates of obesity are generally higher among women than men and, in affluent countries, rural-dwelling women have higher rates of weight gain and obesity than urban-dwelling women—in Australia, young women living in rural and metropolitan areas gain an average of 700 g and 550 g per year, respectively. A pragmatic cluster randomized controlled trial randomly assigns groups of people (here, women living in different towns) to receive alternative interventions and compares outcomes in the differently treated “clusters” under real-life conditions.

What Did the Researchers Do and Find?

The researchers assigned 41 Australian towns to receive a 1 yr self-management lifestyle intervention (HeLP-her) or to act as controls. The intervention consisted of one group session during which facilitators delivered general health information and five simple health messages (for example, try to eat two servings of fruit and five servings of vegetables a day), a program manual to help participants develop a personalized weight gain prevention strategy, monthly text message to remind participants of key behaviors for weight gain prevention, and a 20-min personal phone coaching session delivered three months into the trial. Participants in the control clusters received a group education session on general women’s health topics at the start of the trial. In total, 649 women with an average baseline BMI of 28.2kg/m2 participated in the trial. After one year, the average weight change was +0.44 kg in the control arm of the trial and −0.48 kg in the intervention arm (a between group difference in weight change of −0.92 kg). The intervention also improved diet quality and self-management behavior and was equally efficacious across all age, BMI, income, and education subgroups.

What Do These Findings Mean?

These findings suggest that a low-intensity lifestyle program can prevent persistent weight gain among women. Specifically, the year-long HeLP-her intervention prevented a weight gain of nearly 1 kg on average among women living in rural Australia. Notably, a recent modeling study estimated that a 1 kg weight loss, if applied across the US population, could avoid 2 million cases of diabetes, 1.5 million cases of cardiovascular disease, and more than 73,000 cases of cancer. Although it is difficult to identify the successful elements of any intervention that targets multiple behaviors, key components of the HeLP-her intervention probably include the use of simple, non-prescriptive health messages, the focus on small behavioral changes, regular self-weighing, and the use of both personal and electronic means to deliver the intervention. Some aspects of this trial (for example, nearly a quarter of the participants did not complete the trial) may affect the accuracy of its findings and a longer follow-up is needed to determine the long-term effects of the intervention. Nevertheless, these findings provide new information on effective weight gain prevention strategies that align with current clinical guidelines and population strategies designed to halt the global rise in obesity.

Additional Information

This list of resources contains links that can be accessed when viewing the PDF on a device or via the online version of the article at http://dx.doi.org/10.1371/journal.pmed.1001941.