- The two groups both received counseling only for the first six months. After that, one group continued to receive monthly counseling, while the other just used a "fitness device". The way the summary (and the linked story) are written seemingly implies both groups were receiving counseling the entire time, which is false.
- The device used in this study sounds like something the researchers cobbled together. The researchers also "made a web site" where participants could review the data from the device. This does not really seem comparable to even fairly cheap modern fitness trackers, where feedback and data are easily obtained anytime the user wants. These guys really should have used brand name off the shelf commercial trackers if they really wanted to validate their conclusions.
All in all, this study seems to have some significant problems.