4. Discussion
weight gain, eating behaviors, weight loss
SECONDARY
This secondary analysis supported that on average, an intervention focused primarily on physical activity has a modest effect on change in weight in adults. Similar to the parent study [Despite the lack of differences in weight loss between the intervention conditions, this study showed variability in weight change in response to the intervention conditions, with some subjects having weight gain, weight stability, or weight loss. This difference in weight change does not appear to be a result of differences in physical activity, as this study showed that all categories of weight change had similar increases in physical activity. Thus, this study further explored whether eating behaviors may have contributed to differences in weight change and did not detect differences in energy intake between the weight change categories. However, self-report was used to assess energy intake and macronutrient composition, which may have contributed to the inability to detect meaningful and statistically significant differences. The inability to detect differences in energy intake in response to supervised exercise was also reported in studies that have used cafeteria-style measures that involved plate waste [King et al. examined compensators (less weight loss) and non-compensators (greater weight loss) in response to a 12-week supervised exercise intervention [The systematic review and meta-analysis conducted by Beaulieu et al. [There are additional important findings from this study that warrant consideration. First, while the average weight loss across the physical activity interventions was approximately 1% to 2%, the individuals identified as meeting the criteria for weight loss (>3% decrease in weight compared to baseline weight) had an average weight loss of approximately 6%. It has been suggested that weight loss of at least 5% is associated with improvements in a variety of health-related outcomes [The findings of this study should be considered within the context of its potential limitations. This was a secondary analysis of data with participants grouped by weight change status post hoc, and this may have allowed for unmeasured bias that influenced these findings, which warrants consideration. This study also included a self-report of physical activity that did not include measures of sedentary behavior, occupational physical activity, or household physical activity. Thus, some components of physical activity were unmeasured, which, combined with the self-reported nature of the assessment completed, may have influenced these findings. This may suggest the need to include valid and reliable measures of energy expenditure and all components of physical activity in future studies that examine the effects on weight change. This study also used a self-reported measure of energy intake, and future studies should consider other methods of assessment. However, despite their objective nature, even direct observation, plate waste measures, and the use of doubly labeled water have limitations that will also need to be considered for the assessment of energy intake. The inclusion criteria for this study also limited the sample to adults within a BMI range of 25 to <30 kg/m