British weight loss expert Steve Miller is justifying his fat-shaming activities as something that's done out of love.

He wants today declared "tell a friend they're chubby" day.

Steve Miller told Tim Dower it's obesity can lead to cancer and diabetes, and it's ok to do this if you really love someone and want them to live a good long life.

"If that person is getting too fat and let's face it, it's quite easy to get too fat these days, then I think you're absolutely fine if you put your arm around that person and you say, 'I'm really concerned about you'."

But Miller has drawn approbation from all corners of the globe.

He says it's all about health, not embarrassing people.

"I think we have to be honest about it. What we don't do is bully people - there is a big difference here."