Paula Bennett has revealed she underwent gastric bypass surgery before last year's election.
The former Deputy Prime Minister said she had "battled with my weight all my adult life", and she hopes to send a positive message to others struggling with their weight.
"On one hand it's no one's business but mine, but… I wanted to be upfront with others who struggle about the choice I made," she wrote on Facebook.
"The best reason for going public is I feel great about my decision and don't care what others think. So haters can hate - I'll just keep ignoring them and do the best I can both personally and professionally."
She told NZME she's been mulling over whether to get surgery for years.
Gastric bypasses shrink the size of the stomach, so patients feel full quicker and eat less. The surgery is publicly funded for those who meet the criteria, but the Upper Harbour MP had her operation at a private clinic.
In 2016 she told website The Spinoff she had been subjected to "personally cruel" jibes about her weight.
"I am recovering well and getting used to my new diet," she told NZME.
"I can't wait to get back to working the electorate next week and next month with our big National team in Wellington."