Kiwis who put on weight last year did so 10 times faster than normal, according to a new survey.
But essential workers such as police and nurses managed to keep it off, says ExerciseNZ chief executive Richard Beddie.
Last year was a stressful one for most, thanks to COVID-19's arrival on our shores. The country was plunged into a strict lockdown in March to wipe out the virus amid predictions thousands would die if it was allowed to spread.
Many passed the time at home by discovering - or rediscovering - a love of baking. ExerciseNZ's survey found that helped spur a nationwide weight gain of 2.8 million kilograms - about the same weight as 500 elephants.
Those who reported putting on weight gained an average of 5.4kg - 10 times the usual rate of weight gain according to ExerciseNZ, a non-profit that represents the health and fitness industry.
"Stress is the big driver here," said Beddie. "The thing that's probably surprising is the scale of it."
But it can't be entirely blamed on sourdough, he says. New Zealand is one of the few countries in the world that managed to stop the virus spreading, and Kiwis have for the most part enjoyed fewer day-to-day restrictions than the rest of the world.
"If you think about what happened in New Zealand's lockdown, it was relatively short on a global scale," said Beddie. "We're talking about seven weeks... with a few more regional lockdowns in Auckland for a couple of weeks here and there.
"But that means overall, probably 10 months of the year - if not more - we were in relatively normal operation. Something else is happening here - not just around physical activity, not just around eating when we're locked in a home. People are stressed and in a completely different environment post-COVID than they were before."
Gyms were closed during the lockdowns, and have been linked to outbreaks overseas - exercise increases the rate of breathing, which helps spread the airborne virus.
Beddie said stress is probably the biggest cause of Kiwis' unprecedented weight gain, followed by a change in eating habits with people spending more time working from home.
"All of these have accumulated."
The survey also found 20 percent of Kiwis reacted by losing weight - mostly essential workers, the survey found.
"Whether or not you respond by losing or gaining weight, stress does lots to the body," said Beddie.
The good news is almost everyone who exercised regularly before COVID-19 is back to their regular schedule - 95 percent, according to the survey.
"While this is good, we need to look at ways where we can bring the benefits of exercise to the 80 percent of the population who don’t presently take part in any structured physical activity," said Beddie, suggesting people take up subsidised gym memberships available through the ExerciseNZ website.