A new book is taking us on a journey inside the human gut, where a lack of good bacteria has opened the door on a plague of health issues around the world and here in New Zealand.
Dr Michael Mosley stopped by The AM Show to talk about The Clever Guts Diet, and took the time to tell us exactly why we're decimating our gut bacteria.
"One of the worst things we're doing is consuming huge amounts of sugar and huge amounts of antibiotics," he says.
Dr Mosley says the average New Zealand kid around the age of five is consuming their own weight in sugar - around 20kg a year.
"Essentially, your gut was never designed to be hit with that much sugar."
That's destroying the approximate 1.5kg of microbes in your gut - at least 1000 different species.
"The biggest problem is we have all these antibiotics and sugar and processed foods," he says.
"Anything you can buy in a petrol station is probably going to contain emulsifiers, and what they do is they kill of an awful lot of the good bacteria."
"The microbes in your gut, they are not passive - they send signals [and] chemicals to your brain, and they can also hack into your system.
"They send secret messages which can induce cravings and that seems to be one of the ways they do it.
"If you're hitting your system with sugar, you're encouraging the growth of the microbes that like sugar, and you're telling your brain to eat more sugar."