India, Nov. 3 -- Ask ten families which oil is the healthiest and you will get ten different answers. It is a debate that plays out in kitchens, at dinner tables, in family group chats and in neighbourhood conversations across the country. Everyone has an opinion, usually inherited from a parent or grandparent, and most of us cook with the oil we grew up with. Habit is powerful in the kitchen, and it is often the main reason one oil ends up carrying every meal. The real answer is that no single oil does it all. The smarter way to cook is to use a mix of oils through the week, and the government is now giving Indian households the same advice.

This is a useful shift in thinking. For many years, the conversation about cooking oil was frame...