For the first time in human history, children are facing shorter lives than their parents. The reason? Obesity - it's a killer epidemic that destroys millions of lives each year. There isn't a single country that's been able to reduce its obesity rates . . . and unfortunately Kiwis are heavier than most. If the trend continues, we'll see nearly half the world's population as clinically overweight or obese in just 12 years time. But what if there was a silver bullet solution? Well, a team of New Zealand scientists may have found one. Amazingly, it's all natural - but the solution is not for the faint hearted, or the weak-stomached. They believe the cure for obesity could lie inside our faeces. Our 'gut bugs' team will take fit people's poo and feed it to obese people to see if it makes them thin. And surprisingly there's a lot to suggest this theory might not be so crazy. Over the next six months, we'll be following four obese teenage girls to see if this revolutionary treatment actually works. The girls won't be dieting, but they will definitely be on trial as we see their successes and struggles. Along the way, we'll also dive into the cutting edge of science behind the human microbiome, how we gain weight, and why fat can be so stubborn to lose. And it's not just about the girls - the reputations of our team of elite researchers are on the line too. If their theory is right, this ground-breaking treatment could change the lives of every obese and overweight person on the planet. There's just a whole lot of crap they'll have to get through first. Welcome to the secretive world of human poo trials.