Dr Jaqueline Rowarth says it's important to have principles when making decisions about food, but it is equally important to know how your choices could affect other people.
Rowarth spoke to The Country's Jamie Mackay about Country of Origin labelling, saying it is "fascinating stuff," especially when it comes to pork.
New Zealand has very strict animal welfare and environmental regulations and as a result, our local pork products are more expensive, says Rowarth. As well as this, only 40 per cent of pork for sale here is from New Zealand.
"That leaves 60 per cent coming in from countries where they don't have the same care for animals or for the environment, or indeed the humans raising the animals themselves."
As a result of this, New Zealanders end up buying foreign pork products because they are cheaper, while pork from "our industry [which is] following all the regulations ... is just too expensive for people to buy."
Another example of this is concern over battery hens' welfare resulting in free-range eggs which are more expensive. Rowarth says not everyone can afford to buy these products, although animal welfare is very important, it should not be at the expense of poorer families with hungry children.
A recent Greenpeace press release has urged Fonterra to stop using Palm Kernel Extract (PKE) as it leads to deforestation. Rowarth agrees that deforestation is an issue, but stopping it outright is not so easy.
Countries such as Indonesia and Malaysia rely on the palm oil industry and while deforestation will help the environment, Rowarth says we need to help the people as well.
"I do think we need to remember that the money that those countries are getting from the palm oil is going into hospitals and schools and tertiary education and roading. And it's moving people out of cardboard shanty houses or slums."
"We need to be thinking always about the alternatives. If we make a statement from our lovely existence in New Zealand, what does it mean for other people?"