A new study co-authored by a UNC Gillings School of Global Public Health researcher found that two specific diet and exercise strategies prevented weight gain and obesity among young adults over a sustained three-year period.
Findings of the multi-site study, published online May 2 in JAMA Internal Medicine, focused on young adults between 18 and 34 years of age, a range in which the potential for weight gain is highest. The study is titled “Innovative Self-Regulation Strategies Reduce Weight Gain in Young Adults: The Study of Novel Approaches to Weight Gain Prevention (SNAP) Randomized Controlled Trial.”
[Photo: Dr. Deborah Tate]
According to Dr. Deborah Tate, UNC Gillings School professor of health behavior and of nutrition and principal investigator for the UNC study site, the two methods studied – the “daily small-changes approach” and the “periodic large-changes approach” – both resulted in weight gain prevention and some weight loss over the three-year study period. Dr. Tate collaborated on the study with Drs. Rena Wing and Mark Espeland and colleagues from Miriam Hospital in Providence, RI, and Wake Forest University School of Medicine in Winston-Salem, NC.
Dr. Tate says the researchers also found that one of the methods examined in the study was demonstrably more effective than the other.
“Both the large-changes and small-changes methods were effective for preventing weight gain and obesity in young adults, though one was a bit more effective than the other,” Dr. Tate said. “The large-changes approach, which involves making some significant changes to diet and exercise at the program’s outset, resulted in participants losing some weight initially and then maintaining that, which helped to buffer against weight gain for the full three years of the study. The small-changes approach also was beneficial, but the amount of weight lost and subsequently kept off was less.”
Dr. Tate said participants were split into three groups – 200 people made daily small changes; 197 made initial large changes; and 202, who were self-guided, served as controls.
At the outset of the study, researchers met with the small- and large-changes groups 10 times over a four-month period to develop skills and an approach to diet and exercise that would help with weight-gain prevention during the high-risk period. A key element of both approaches was daily weighing, to monitor weight gain or loss and to guide diet and activity changes over time.
The large-changes approach encouraged an initial weight loss to serve as a buffer against small gains that typically occur over young adulthood. It targeted a five-pound weight loss for those in a normal/healthy BMI range and a 10-pound weight loss buffer for those above normal BMI, who were overweight at study outset. The large-change group reduced calories by 500 to 1,000 calories per day for eight weeks, while gradually increasing activity levels until they reached a goal of 250 minutes of activity per week. Participants were instructed to maintain exercise at that level for the course of the study.
The small-change participants were given plans that reduced their diet by 100 calories per day from baseline and were encouraged to increase their activity by about 100 calories per day. They were given pedometers and instructed to add 2,000 steps of activity daily – or about one additional mile of walking – and to maintain those levels for the length of the study.
Assessments of all the participants’ weight, BMI and body composition occurred at the study’s outset, at the four-month point, and again at the one-, two- and three-year anniversary dates of the study’s start.
The researchers found that both the small- and large-change groups were able to prevent weight gain over three years.
“These findings are very important for public health,” Dr. Tate said. “Until now, we didn’t have clear guidance on what the message and recommendations should be for preventing weight gain. This study showed that frequent weighing – and either initial weight loss or daily small changes to both diet and activity – resulted in successful weight-gain prevention during a high-risk period of adulthood. More importantly, due to the success of these programs, we received funding to continue them and to follow participants to see the effects at six years.”