In this Food Unwrapped diet special, Jimmy Doherty, Kate Quilton, Matt Tebbutt and guest presenter Kiran Jethwa cross the globe to unearth the very latest dietary trends and scientific advances in the world of weight loss. In Los Angeles, home of the body beautiful, Kate investigates reports that caffeine could be a powerful secret weapon in the battle of the bulge. Could a double espresso really help us burn extra calories, even after we finish exercising? Kate meets one of California's leading sports scientists to find out. Jimmy visits Belgium on the trail of the dieter's holy grail: a chocolate that could be good for you. The secret? It's a probiotic chocolate bar, packed with bacteria that are supposed to keep us healthy and even help us stay slim. But how does probiotic chocolate stack up against other gut-friendly foods such as sauerkraut or yoghurt?

Jimmy Doherty, Kate Quilton and Matt Tebbutt return with a new episode, uncovering more unusual, intriguing and surprising secrets behind the food we eat. Kate looks into coloured crisps. In Chile she finds out how these rainbow snacks get their colour, and discovers why the common white potato is king of the crop, despite the other fantastic options on offer. Meanwhile, Jimmy investigates one of the trendiest items on our shelves: avocados. But the rapidly rising demand for these fantastic fruits has led to alarming reports of a crime wave hitting growers. A trip to an avocado farm in Spain reveals the extent of the problem, and also sheds light on the secret to making a lovely green guacamole. And in Belgium Matt finds out about one of the tangiest tipples on our supermarket shelves: sour beer.