Statistic of the day

Something’s clearly amiss in this London Times story, reporting on a beer industry study of obesity and beer drinking:

 

“The study shows that the risk of obesity is almost 30 per cent lower for those consuming over seven days per week as opposed to two to four days.”

 

http://women.timesonline.co.uk/tol/life_and_style/women/article6279955.ece   Maybe I don’t understand the measure here. The Imperial Gallon is bigger than the U.S. gallon. Maybe there’s an Imperial Week as well, with more than 7 days in it.