A Rotorua family walks into Pak'nSave in 2014. Their annual grocery bill: $7,683. The year before, that same family spent $15,317. The year before that, $15,295. For four straight years, their food costs hovered around $15,000. Then, in a single year, it collapsed by half.

This isn't a sale. This is what happens when a city stops buying food.

Rotorua's 2014 food expenditure is the lowest it's been since 1993. You have to go back 21 years to find anything comparable. From 2010 to 2013, the city's households consistently spent between $14,500 and $15,300 annually on groceries. Then 2014 hit, and the bottom fell out. (Source: Stats NZ, food-price-index-detailed)

When food spending drops this sharply, it's not because prices fell. Food price indices for the period show modest increases nationally. It's because people stopped spending. They lost income. They left town. They started going without.

Rotorua in 2014 was a city reeling. Tourism hadn't yet recovered from the global financial crisis. Forestry, the region's other economic pillar, was struggling with low log prices and reduced demand from China. Unemployment was high. The city had one of the highest rates of benefit dependency in the country.

A 50% drop in household food spending doesn't happen in a functioning economy. It happens when jobs disappear faster than people can adjust. When entire households shift from working to not working. When the economic base of a city erodes so quickly that people either leave or survive on drastically less.

The trajectory tells the story: steady spending for four years, then a cliff. From $15,317 in 2013 to $7,683 in 2014. That's not a gradual adjustment. That's a rupture.

Food is the last thing families cut. You can delay car repairs, cancel subscriptions, skip holidays. But you still need to eat. When food spending halves, it means every other option has already been exhausted.

Rotorua has since recovered somewhat. Tourism surged in the late 2010s, bringing jobs and income back to the city. But 2014 stands as a marker: the year a regional centre's economy collapsed so completely that its residents spent less on food than they had in two decades.

The data doesn't tell us where those households went or how they survived. It just shows the hole they left behind: a city that, for one year, stopped eating like it used to.