From a colleague:

"People can and do maintain weight loss. For example, look at the National weight Control registry in the USA"

My response:

The National Weight Control Registry is a list of people (10,000 in the US, so the equivalent here would be 750 people out of Australia's population) who have enrolled themselves after losing 14kgs or more and keeping it off for a year. It relies on self-reported data and people who regain weight are removed from the registry. It is not representative of the population or of the usual experience and was never meant to be such. However, it does tell us a bit about the statistical unicorns who consider their weight loss important enough to enrol on the registry, and who's bodies have thus far allowed weight suppression. The behaviours these people maintain are: 60+ minutes of exercise every day, a strict (usually low fat) diet every day with no exceptions (not even Christmas), they eat breakfast every day and they weigh themselves weekly to daily. They have made maintaining their weight loss one of the most important things in their life. How many of us tell our clients that if they want to lose weight and keep it off that they need to develop this degree of rigidity forever and with the caveat that those behaviours will also not necessarily result in weight suppression? And for questionable longevity benefit when compared with behaviours alone.

Their response:

"Weight loss is not necessarily temporary. The National Weight Loss registry as you mentioned doesn’t have the massive numbers you desire, but they shouldn’t be dismissed as anomalies or outliers. For a start, not many people actually know about it to register themselves in the first place."

I did not respond as the conversation moved on but what I would have responded would have been:

They are literally outliers. That is literally what outlier means.

The wonderful Ragen Chastain of 'Dances with Fat' has a great blog post on this too: www.danceswithfat.wordpress.com/2012/12/27/national-weight-control-registry-skydiving-without-a-chute/

And from fellow dietitian Glenys Oystan from 'Dare to Not Diet': www.daretonotdiet.wordpress.com/2016/05/31/the-nwcr/