That's not the cost of living, then. It's the "cost of starving and/or freezing to death while not going anywhere". Like that's a number we care about. But I

That's not the cost of living, then. It's the "cost of starving and/or freezing to death while not going anywhere". Like that's a number we care about. But I suspect that Krugman's point (even if he expressed it badly) is that food, energy, and fuel are more noisy - more seasonal, but also have more noise in other ways. Well, if you want an early warning of which direction the economy is going, you don't want the noise, because if you mistake it for signal, you're going to be misled. So an economist may well find such a number more useful.