- David Ludwig: Conventional wisdom used to be that cutting back on fat would make us lean and healthy
- The science of nutrition is complex, but we know that the low-fat diet of the last 40 years didn't work, he says
David Ludwig is professor of pediatrics at Harvard Medical School and Boston Children's Hospital, and the author of the book "Always Hungry? Conquer Cravings, Retrain Your Fat Cells and Lose Weight Permanently." Follow him on Twitter and Facebook. The views expressed in this commentary are his own.
(CNN)Normally, science advances by trial and error. When an experiment fails, researchers question assumptions, formulate new ideas and then design better studies. But the field of nutrition is having a hard time of this when it comes to the low-fat diet debacle.