She attracted some generous and unexpected sponsors who donated money to the cause, including an acquaintance who phoned to offer $50, students from the Gonville School class where she's a helper who chipped in to give $12, and two young women serving coffee at a local petrol station.
"I told them the coffee smelled good but that I couldn't have any, and explained about Living Below The Line. They were very interested and immediately dug around in their bags and came up with $23 to donate.
"It really touched my heart."
Mrs de Jongh said she was extremely grateful to everyone who supported her.
"A lot of people said they couldn't do [the challenge] themselves but they agreed to support me, so they were able to participate in that way."
Mrs de Jongh said although she managed, the challenge was definitely that - a challenge.
"I wasn't full of energy by the end. It really gave me a feel of what eating on the poverty line is like. I ate a lot of rice and a lot of oats, and a few cheap vegetables.
"The only protein I could afford was an egg."
Mrs de Jongh said she missed her regular flat whites the most.
"I bought very cheap instant coffee, but soon realised that one cup of coffee was not enough for me, so I did give up some food to have an extra cup of coffee."
Living Below The Line this year raised $124,000 in New Zealand, with a combined global total of more than NZ$4 million.
Global funds are used to fight extreme poverty, funds but in New Zealand go towards Tear Fund's anti-trafficking and exploitation partners to help them free and rehabilitate women and children forced into sexual exploitation and to help authorities prosecute those responsible. It's estimated for every trafficker prosecuted, 120 potential trafficking victims are saved.