A trip to California reveals the secret of perfect walnuts. Plus, what makes sour sweets sour? And how do brewers make their trendy hazy beers cloudy?

Kate Quilton looks into Britain's plastic crisis while Jimmy Doherty and Matt Tebbutt visit South Africa on a piquanté pepper hunt.

How can there be so many tomatoes in a tomato ketchup bottle? When did oysters go from Victorian bar snack to luxury food? And the truth about medium vs large eggs.

Jimmy heads to Paris to find out why baguettes go stale so fast. Matt checks out buffalo mozzarella in Italy. And Briony May Williams discovers the surprising secret to how mushy peas get mushed.

Can coffee help you sober up? Kate investigates trendy drink kombucha and meets people who are turning it into clothes! And which cut of beef do thin-cut steaks come from?

Kate visits France to find out if a glass of red wine a day keeps the doctor away. Matt lifts the lid on skimmed milk. How do dairy farmers get exactly the right amount of fat in every pint of milk?

Kate wants to know where liquorice comes from. She's not a fan, but will she be converted once she's seen the experts in Calabria, Italy turn bitter-tasting liquorice roots into sweet treats?

Jimmy discovers that there's more to traditionally-matured cheese than meets the eye, thanks to a microorganism that helps give the likes of pecorino their distinctive hard rinds

Are ready meals really twice as big as they were in the 1950s? How do green soy beans become creamy white tofu? And can artificially inseminating cows make milk easier to digest?

Jimmy explores new ways to get crabs to come out of their shell. Kate finds out how to get children to eat their greens. And how are gummy sweets made? Matt investigates.

Jimmy Doherty explores how blood is becoming trendy in gastronomy, including blood meringues. Kate Quilton asks why Spanish melons are so juicy, and Matt Edwards finds out how rock is made.

The gang dig up more fantastic food facts. Are shallots actually small onions? There's a price query about the cost of baked potatoes. And what's wrong with sheep's milk?

How many apples are there in a can of cider? How does a humble vegetable become trademarked? And is the white stuff on salami something we should be talking about?

The team uncork the mystery of wine and hangovers. Amanda Byram explores peas and the plastic pollution problem. And why doesn’t shop-bought grated cheese stick together?

Jimmy Doherty fires up the barbecue and asks why we suddenly all love brioche for our burgers? Plus, the truth about wine bottles and why some ice creams get melty and messy much faster than others.

Jimmy investigates turmeric in India and Kate finds out how much milk is in chocolate, while Andi draws the short straw and investigates asparagus and pungent pee problems.

Some favourite investigations as Jimmy Doherty looks at how our national dish could become squid and chips, Kate Quilton reports on kangaroo meat, and Matt Tebbutt looks at pesto.

Can eating too many poppy seeds make you fail a drugs test? Kate learns the consequences of tipping cooking oil down the drain. Plus: ancient grain bread.

Could a threat to British juniper berries spell the end of the gin resurgence? Plus: Kate checks out macadamia nuts in Hawaii and Matt finds out what's so bad about his double dipping habit.

Was Edam once used as cannonballs? What's that white powdery stuff that sometimes forms on chocolate? And can bedtime teas really help us sleep?

Jimmy gives supermarket fish a sniff to discover how fresh the stock really is. Kate investigates how asparagus can be grown all year round in one of the driest places on earth - the Ica Valley, Peru.

Are fresh sardines better for us than tinned sardines? How much is known about the ducks we consume? And, when it comes to pasta, is fresh best?

How do those chunks in American ice cream stay crispy? Why have olive oil prices been going up? Why are Bloody Marys so popular on planes and why does airline food taste so different at ground level?

Jimmy investigates whether manuka honey has any medicinal properties. Kate discovers why some varieties of caviar are so much cheaper than others. And Matt visits a Scottish distillery.

Does a happy chicken lay a tastier egg? How do the supermarkets get avocados 'ripe and ready'? And why does one type of balsamic vinegar cost 100 times more than another?

Can hot chilies injure you? What's the difference between outdoor-bred and outdoor-reared pork? And what's bugging Jimmy about red food dye?

Kate investigates the worrying rise in peanut allergies. Matt traces the British blackcurrant from the field to the Ribena factory. Jimmy's on the trail of a surprising food fraud: oregano.

In China, Matt Tebbutt helps to cultivate pearls from surprising creatures. And why does sliced ham sometimes have a weird rainbow pattern on it?

Why is there jelly in our pork pies and how does it get there? What in nature provides the natural bright blue dye in our sweets? And why is soft shell crab such a delicacy?

Kate meets a tech start-up who hope to feed the world by growing fish flesh in a dish. Plus: how do you make ice cubes that aren't cloudy? And why can't you put papaya in jelly?

How much orange is in orange squash? Why's maple syrup so expensive? And what's with all those little holes on biscuits?

Jimmy discovers why caviar is so expensive. Kate reveals how a malty unsung hero is made. Plus: muesli.

Favourite investigations. Jimmy Doherty visits Europe's biggest brewery. Kate Quilton challenges Matt Tebbutt to make crumpets. And Matt discovers why maple syrup is so expensive.

Why are some vanilla ice creams more expensive than others? Are baby carrots really babies? And how can coffees have lots of flavours when they use just two types of coffee beans?

In Italy, Jimmy looks into why Parmesan costs up to twice as much as supermarket Cheddar. Kate's been puzzling over paprika and travels to Hungary and Spain to find out exactly where it comes from. And Matt looks at hard-boiled eggs - it can be fiddly enough getting the shell off in the comfort of your own kitchen, so how do the big players manage it now that hard-boiled eggs are popping up everywhere in supermarkets?

Jimmy wants to know why so much of the bacon in supermarkets comes from Denmark. Kate meets mozzarella makers in Italy. What is the liquid that mozzarella balls are bobbing in?

Jimmy Doherty finds out why Iceland supplies most of our cod. Kate Quilton investigates whether the banana's days are numbered. And Matt Tebbutt discovers why popcorn doesn't fill you up.

More fun facts about our food, including: why some fruits are hairier than others, the difference between single and double cream, and the science of why canned food keeps for so long.

What gives some whisky its smoky flavour? Why doesn't halloumi melt? And how do you get corn off the cob?

The team ask: Why are cashew nuts never on the supermarket shelf in their shells? What exactly is scampi? Does expensive salt taste different to cheap salt?

How do you milk a camel? Kate investigates, and explores camel milk's rising popularity. How does supermarket fresh pasta last so long? And should we buy supermarkets' standard products or value ones?

Is a parasite hiding in your sushi? Can M&S really trace all their beef burgers back to the cow? Plus: Matt investigates concerns about naturally-occurring arsenic in baby rice products.

Recipe boxes are increasingly popular - but are they good value? Does it matter what kind of water you drink? And Jimmy Doherty reveals the best way to remove the smell of fish.

Briony May Williams finds out why some radishes are hot. Andi Oliver asks why pre-made sandwiches contain mayonnaise. And Kate Quilton discovers how truffles are grown.

Amanda Byram is plunged into darkness in the rhubarb triangle. How much sugar is in milkshakes? And Matt Tebbutt investigates sunflower seeds.

Why does pasta come in so many different shapes? How much butter is in buttermilk? And how do ready meals get their spice rating?

Kate's in Kenya wondering how do cold-brew and iced-coffee differ? News from Staffordshire on why parsnips are so sweet. And do frozen pastries taste as nice as fresh pastries?

The team explores how the UK food industry is meeting the challenges of climate change - from cucumber wrapping and pumpkins at Halloween to beef production and meat substitutes.

Matt Tebbutt is in Spain learning why some oranges are so hard to peel, while Jimmy Doherty heads to Thailand to discover why coriander is the herb of choice for some, but for others it seems to taste like soap. Briony Williams finds herself in a bit of a jam as she interrogates an important kitchen conundrum - why dropped toast always lands the wrong side down

Jimmy visits Bulgaria to find out why rose oil is considered liquid gold. Kate tackles pink pork; is it safe to eat? Matt gets the inside story on oven bags.

Kate Quilton travels to Swaziland to find out how they get tinned grapefruit so perfect, and, in Finland, Matt Tebbutt discovers exactly what the bacteria are in Probiotics.

Kate and Matt investigate the wax on our lemons in Spain and Thailand, and Matt gets the real story behind formed ham here in the UK.

Kate visits Rome to find out what the difference is between gelato and ice cream. Plus: are dark rum and white rum made with different ingredients? And why do mints make your mouth cold?

What gives fizzy sweets their fizz, and can you harness their explosive power in a rocket? One in five of us lack vitamin D; can mushrooms help? And is raw kale bad for you?

Helen Lawal heads to one of the world's biggest coffee factories to find out how instant cappuccinos get their froth. Matt Tebbutt is in Naples to discover why most tinned tomatoes come from Italy, while Kate Quilton embarks on a panettone odyssey across Europe to learn how the fluffy cake lasts so long.

Jimmy finds microplastics in some of our most popular soft drinks. Kate Quilton tackles nettles. And Amanda Byram asks why do rhubarb and custard go so well together?

Matt Tebbutt visits Argentina to learn the secret of perfect popcorn, Andi Oliver looks at how the mould gets put inside blue cheese, and Jimmy Doherty is in Germany to see how electricity is used in cutting edge crisp production.

What's the healthiest lettuce in the salad bag? Is sea salt all it's cracked up to be? And in Suffolk, Briony May Williams explores the difference between light and dark ales.

The gang find out how much meat is in your sausage and where orange wine gets its colour. And Amanda Byram tests a high-tech solution for the perfect slice of millionaire's shortbread.

The gang find out what exactly locust bean gum is. Also, why is strawberry juice so elusive at the supermarket? And in the Orkney Islands, Matt uncovers some very special residents.

Jimmy investigates mineral water and whether tap water has really been through seven people, while Kate finds out what the vegetable is in vegetable oil.

Jimmy finds out what whitebait actually is and why it's not available in most supermarkets. Kate visits a cattle farm in America that supersizes cows and asks if what our meat eats matters.

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?

How do crumpets get filled with holes? How come baby food has such a long shelf-life? And why's mascarpone more expensive that other soft cheeses?

What exactly is processed meat, and is a fresh British banger healthier than a frankfurter? Jimmy investigates dates. And Matt meets a man who has 250 varieties of apple on his tree.

Why's clotted cream yellow? Could squid and chips replace fish and chips as our national dish? And where do multivitamins come from?

What are those worms doing in bottles of tequila? How do you stop carp tasting of mud? And what's the difference between tangerines, mandarins, satsumas and clementines?

Kate discovers how the way that you drink tea can affect its taste. Matt investigates the difference between bubble gum and chewing gum, and discovers an unusual use for used gum. Plus: lentils.

Jimmy Doherty asks what offers better value: growing your own fruit and veg or buying from the supermarket? Plus, investigating the illegal trafficking of eels, and ginger beer.

Why is the shelf life for a vegetable stir-fry mix so short? What's the secret to making perfect layers in a rocket ice lolly? And in Portugal, Kate investigates piri-piri.

Is there any goodness left in tinned tomatoes? What part of a pig makes sweets chewy? And how do prebiotics work?

How did sticky rice get its name? Can cream crackers help with weight management? And is cabbage really a saviour for breastfeeding mums?

What do Italians think of the extra-virgin olive oil sold in our supermarkets? Does drinking hot milk help you sleep? How wild is wild boar? And how much truffle is in truffle oil?

Should we keep coffee, tomatoes, potatoes and even red wine in the fridge? Kate finds out why eucalyptus is so good at clearing our airwaves. Plus: sauerkraut.

This episode explores how prawns are intensively farmed and discovers why there are often so few wild mushrooms in our wild mushroom soups. Kate flies to Thailand - the world's biggest producer of farmed prawns - to get a sense of the scale of the industry, and Matt meets a professional wild mushroom forager in the woods of West Sussex.

Jimmy finds out how food producers are using seaweed to reduce their salt content. Jellied eel sales are booming, but where do the eels come from? And why does tonic water glow in UV light?

How do you farm crocodiles? Kate visits Australia to find out and collects crocodile eggs from under their mothers' noses. Does cod liver oil have to be cod? Why do bagels taste different from bread?

At a green bean plantation in Kenya, Jimmy learns how they grow the beans so straight for the supermarkets, and finds out what happens to the beans that don't make the grade. He also discovers the remarkable lengths that the farmers go to to stop the local wildlife destroying their valuable crop. At a Norwegian scallop farm, Matt braves the icy waters of the North Sea to join the divers harvesting scallops by hand from the sea bed. This sustainable farming method could be a model for the rest of Europe, but it needs a constant source of baby scallops, so Matt gets hands-on in the hatchery as he learns how to encourage a scallop to procreate. And Kate tries to unravel a mystery about Cornwall's most famous local delicacy: what exactly goes into a Cornish Pasty, swede or turnip?

Matt Tebbutt is in Fray Bentos, Uruguay, looking for the 'corn' in corned beef. Also, what makes some snacks so moreish? And what's the difference between Scottish Whisky and Irish Whiskey?

Why is halloumi cheese a subject of great debate? Is there a lethal poison lurking in apple cores? And what lives inside every sourdough loaf?

Jimmy Doherty, Kate Quilton and Matt Tebbutt reveal more unusual, intriguing and surprising secrets behind the food we eat. Matt heads to Italy to find out how supermarkets can sell pesto at an affordable price when the traditional ingredients are expensive. He visits one of Europe's biggest pesto producers and takes a remarkable trip to the bottom of the Mediterranean Sea, where basil is being grown in an extraordinary underwater farm. Jimmy wants to know why so many cockles in our supermarkets come from abroad, when he always thought of them as a quintessentially British staple. He visits Wales and the Wash, where two very different stories unfold, and witnesses a remarkable method of cockle gathering that has to be seen to be believed. And why do marshmallows go so crispy and melty at the same time over the campfire? Kate takes a colourful trip around Europe's largest marshmallow factory to find out.

Jimmy learns about a potentially devastating Greek yoghurt by-product. Kate uncovers the secrets of saffron, and Matt finds out why you can't eat kidney beans raw.

Jimmy Doherty looks into skyr, a mysterious yoghurt-like product that claims to be entirely fat-free, but has a surprisingly creamy texture, while Kate Quilton heads to one of the busiest oyster hatcheries in France, where she witnesses the amazing science that goes into providing oysters year-round. Plus, Matt Tebbutt wants to know if the dried strawberries in his cereal are real or just a clever imitation.

Jimmy's off to Israel on the trail of an elusive fruit - the fresh date. If raisins are dried grapes and prunes are dried plums, then what exactly are dates? Jimmy's search for the answer takes him to a vast water purification plant, where they harness the raw sewage of Tel Aviv to turn barren desert into fertile farmland. Kate flies to California to investigate why almond butter is more expensive than other nutty spreads, and discovers a combination of extreme weather and global economics have made the price of almonds go completely nuts. And Matt's in Scotland, investigating haggis. He makes a surprising discovery about the dish's true origins - and then faces the nerve-shredding ordeal of delivering some highly unwelcome news to an unsuspecting audience.

Are there wasps in fresh figs? Why is ostrich meat red? And Kate's mission to give up added sugar reveals some shocking truths.

The team head to Thailand to find out what seafood goes into seafood sticks, and then discover how some British wine is really made... in Spain. In a seafood stick factory in Thailand Kate sees some incredible production techniques and giant frozen blocks of fish called surimi. Confusingly, there are two types of domestically produced wines: British and English. British wine is much cheaper, so what's the difference?