Weight Loss Pill

Megan McArdle points to a John Tierney article about a new medical study about "a new appetite-suppressing drug, tesofensine, [that] was twice as effective as existing drugs in helping people lose weight." The assumption seems to be that a weight-loss drug would produce the health benefits of losing weight.

Count me as dubious. I'd bet that if you have an unhealthy diet and an unduly low amount of exercise, losing weight via a pill would not produce the same benefits (or any benefits at all) as if you changed your diet/exercise habits. By analogy, statins work very well at lowering cholesterol, but they're not nearly as good at reducing mortality (and some combinations might even contribute to cancer). According to a Business Week article:

Wright had a surprise when he looked at the data for the majority of patients, like Winn, who don't have heart disease. He found no benefit in people over the age of 65, no matter how much their cholesterol declines, and no benefit in women of any age. He did see a small reduction in the number of heart attacks for middle-aged men taking statins in clinical trials. But even for these men, there was no overall reduction in total deaths or illnesses requiring hospitalization—despite big reductions in "bad" cholesterol.

My guess is that if your diet and exercise habits are unhealthy, taking a pill won't compensate for it, regardless of whether the pill causes changes that are sometimes a proxy for better health (such as low cholesterol or less weight).