The most painful lesson from alcohol and tobacco control is that profit motive can trump all other concerns. The right preventive measures should be put in place early on, and then need to be vigorously defended against the tidal wave of deregulation, to strike the right balance between legal availability and protecting public health.
Medical schools almost completely ignore the topic. Biomedical funding agencies mostly give it a pass, at best dedicating only a small percentage of their funding for nutrition research. The public therefore must fend for itself when trying to understand which nutrition information is correct and which is not.