And she did! Not only that, she's going to keep at it in 2014.
The rules are simple: two (now three) year-old Johnny's toys and clothes would all be swapped, hand-me-downs or made at home - and disposable nappies would be swapped for reusable ones. Johnny would eat what mum and dad ate - no snack bars or kids' ready meals - and family activities would all be free.
She set about documenting her year of thrifty family life on her blog, Free Our Kids, taking note of the challenges of the frugal lifestyle as well as her delight at uncovering a network of websites and local community drives that make 'freecycling' and swapping a viable way of life.
Hattie's interest in keeping her son away from consumerist culture wasn't purely intellectual. She was unexpectedly made redundant from her job as a journalist, and she and her husband soon realised they needed to make drastic cuts.
It was as they examined their spending that the idea for the project came about. Hattie asked herself which of the spends were actually making her family's life better and easier.
"It wasn't about deprivation," said Hattie in her interview with Chicago's WGN network. No character-building hardship here - Hattie simply suspected that cutting out consumerism might be a positive change.
And she was right, she says. With 2013 over - and a new addition to the family, baby Frida - Hattie and her husband say they are happier and healthier than before, and have decided to stick to their experiment into 2014.
Watch the video interview with Hattie above for more on her story.