(Or why it's not about exercise)
The study is entitled, "A Program Promoting Exercise and Active Lifestyle". In it, 196 overweight (average BMI nearly 30) carefully selected for motivation and affinity to start exercising individuals were asked to exercise at moderate to vigorous intensity for 60 minutes a day, 6 days a week, for a year! To ensure objectivity, subjects were provided with logbooks and heart rate monitors and adherence was excellent. Men in the study averaged 370 weekly minutes of exercise, and women 295.
Subjects were not instructed to make dietary changes.
So if weight loss were about exercise, certainly you would expect that after a year of an hour a day, 6 days of week of exercise, that weight would be lost in a dramatic manner.
Over the course of the year, men lost an average of 3.5lbs and women 2.6lbs.
Readers of my blog will know that I'm all for exercise - reason being is that it's one of the single most important determinants of health and that doing it psychologically bolsters patients who've lost weight and helps them keep their focus on their weight loss behaviours (including dietary changes).
Clearly what it won't do is by itself lead to dramatic weight loss.
Therefore I would argue that studies and public health interventions for obesity that focus exclusively on exercise or increasing day to day activity can no longer be considered ethical as we know that the outcomes will be dismal. My other concern of course is that since we know these interventions are doomed to failure, by throwing public health care dollars at interventions whose success will be measured on the basis of weight, we're going to drain the pot of public health dollars for obesity treatment and potentially make it less likely to receive funding in the future from once burned, twice shy stretched federal, provincial and municipal governments.