For the last several decades, we have dutifully heeded the advice of doctors and health experts regarding limiting dietary fats. Compared to our parents and grandparents, our consumption of fats is dramatically lower, and dramatically different — thanks to dubious inventions such as margarine and canola oil. Only recently has the medical establishment reversed its prohibition of saturated fats and debunked the 1950s hypothesis that saturated fat causes heart disease. But the ideas we grow up with can be hard to dislodge. Most of us have been drinking skim milk since we were kids and choosing non-fat and low-fat options wherever we find them.