Weight gain tends to creep up on us: studies show that young adults typically gain about a pound and half a year. This might not be noticeable from year to year, but over decades it can add up to significant extra weight if it goes unchecked. Gaining weight can be particularly harmful for young adults, perhaps because it’s tough to lose weight, meaning these individuals live with excess body fat for longer. Excess body fat is linked to many types of cancer and other chronic diseases.
The good news is that young adults may not need dramatic changes to diet and exercise to prevent weight gain, as a study recently published in the Journal of the American Medical Association suggests. This randomized clinical trial followed nearly 600 young adults ages 18-35 for an average of three years. About half of the participants had BMIs within the normal range, while the other half were already overweight or obese. The study compared two approaches—small, daily changes to diet and physical activity vs. more dramatic diet and exercise changes—to a control group.
Both intervention groups started with ten in-person meetings, while the control group had only one in-person meeting to provide an overview of the study and the issue of weight gain.
Participants in the small changes group were encouraged to make small daily changes, equivalent to eating about 100 fewer calories or burning an extra 100 calories through activity. The large changes group was encouraged to lose 5-10 pounds to provide a buffer against future weight gain. For the first eight weeks of the intervention, participants were asked to cut 500-1,000 calorie per day. They were also told to gradually increase their moderate intensity physical activity to 250 minutes per week, the amount recommended for weight , and then keep it up until the end of the intervention. Both interventions asked participants to weigh themselves daily and send that information to study staff. In return, participants received monthly feedback.
Each year, both intervention groups had access to online refresher courses. All three groups, including the control group, received newsletters and personalized feedback reports. Height and weight for all participants were measured at baseline, four months, one year, and then yearly after that until the study ended.
Rather than just understanding which group had lost or gained the most weight once the study was over, researchers wanted to capture the cumulative effect of each intervention on weight change, so they averaged the weight change from baseline to each follow up measurement over three years.
After three years, the control group on average gained about half a pound, the small changes group lost just over 1 pound, and the large changes group lost about 5 pounds. The large changes group also had the lowest percentage of participants who gained one pound or more over their starting weight: only about a quarter of this group gained weight, compared to a third of participants in the small changes group. Even more participants in the control group gained weight.
Both approaches seemed equally effective at preventing obesity. While 17% of participants in the control group became obese over the course of the study, half that number became obese in both intervention groups.
Participants in this study were disproportionately female, white, and college educated, meaning these results might not apply to everyone. Nevertheless, this study suggests that while bigger changes may be more effective in producing significant weight loss, small changes can also prevent weight gain over time and lower your risk of becoming obese. These changes can be as simple as choosing lower calorie coffee drinks, slightly decreasing portion sizes, parking farther away from stores, or using the stairs at work. Participants in the small changes study were given pedometers and told to add just 2,000 steps per day, a physical activity goal that is achievable for most of us.
Both the small and large changes approaches also encouraged participants to weigh themselves daily. Frequently weighing yourself can be a good way to help you notice when you’re gaining weight so that you can get back on track. Since both small and large changes seem to be effective at preventing weight gain, choose the approach that you think will work best for you. If you like big, dramatic goals or have a higher BMI and would prefer to lose a significant amount of weight as “insurance” against future weight gain, a large changes approach may be best for you. But if making small changes to save calories or increase your activity sounds more doable to you, go for it!
This study was funded by the National Heart, Lung, and Blood Institute.
For small healthy changes, join AICR’s New American Plate Challenge, a free 12-week online program.