Poor conclusions in the study. 19 lbs lost over 12 months versus 12 lbs lost over 12 months is statistically insignificant. Considering that both groups were on a reduced calorie/moderate exercise program, you could have said that water was the contributing factor (good luck finding a placebo for that, though). Without identifying other contributing factors such as race, family history, or restricting to the exact same diet, this study is worthless.
The article itself cites statistical significance at the .05 level. Other measures were also significant.