Not just in New Zealand. It hurts me when I see people not finishing their plate. I will eat myself sick before I will throw away food. Sadly, this has developed into a bit of a weight problem. And then there's restaurants and supermarkets which throw away enormous amounts of unsold food.

We should buy and cook less food, or maybe have a quick way of sharing left-over food with people who are hungry.

Obesity is now a bigger problem worldwide than hunger.

Is that because hunger has been diminished, or because obesity has increased?

I believe both are true.

I thought I read that obesity is growing faster than undernourishment, but I can't find a source on that now.

It looks like the number of obese [1] and undernourished [2] humans are both currently 700-800+ million.

1. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5477817

2. http://www.fao.org/3/I9553EN/i9553en.pdf

Better to waste than to waist.

(Yes, take less on your plate, save leftovers for future meals, etc.)