The popular press has triumphantly announced that the cause of the obesity epidemic is “junk food.” After a moment’s reflection, however, it seems likely that the true causal structure of the obesity epidemic can be neither single-equation nor univariate. Therefore, while the hypothesis...

The popular press has triumphantly announced that the cause of the obesity epidemic is “junk food.†After a moment’s reflection, however, it seems likely that the true causal structure of the obesity epidemic can be neither single-equation nor univariate. Therefore, while the...