Nutrition matters for everybody, but you can’t major in it at Harvard. Most top scientists go into other fields. Most of the big studies were done 30 or 40 years ago, and most are seriously flawed. The food pyramid that told us to eat low fat and enormous amounts of grains was probably more a product of lobbying by Big Food than real science; its chief impact has been to aggravate our obesity epidemic. There’s plenty more to learn: we know more about the physics of faraway stars than we know about human nutrition. It won’t be easy, but it’s not obviously impossible: exactly the kind of field that could yield secrets.