This is Bagust's second year taking part in the five-day campaign.
"Mathematically very challenging and relatively confronting in terms of a loss of freedom - you can't snack when you feel like it, or go for a coffee when you feel like a coffee - it takes the unconscious and makes it conscious. It brings everyday convenience into focus.
"For me I'll go and go and go, and then I'll hit a wall and my decision-making ability and patience starts to evaporate," she said of doing the challenge last year.
"You feel like your ability to function mentally and physically has become compromised."
She said that made her think about her reasons for taking part.
"I've been to some of the countries where the funds raised will go, and when you're in those places you see people eating rice - and it's a treat if they get soy sauce with it. There are so many things that we are used to - so it's confronting to see the lack of choice, abundance and freedom among people who are eating solely to survive."
Bagust's kids are taking part only for breakfast and dinner, meaning they'd still take packed lunches to school. "It's such a good topic of conversation with the kids - they don't know that butter and milk are a luxury, that it is a privilege that the water they drink is clean."
Last year Bagust went to Nepal and saw first-hand some of the people who had been targeted by traffickers. "They are very vulnerable people, not because they choose to be, but due to the place of their birth and the socio-economic status of their country."
The Live Below the Line challenge runs until Friday.
How to live on $2.25 a day
Breakfast
One egg 25c
Snack
One banana 57c
Lunch
2 pieces of Homebrand wheatmeal bread 10c
32g of cottage cheese spread 40c
Dinner
80g rice 30c
48g of Homebrand tuna (lemon pepper flavour) 60c
For more information visit tearfund.org.nz.