Do you know how much you should drink?

Many global guidelines recommend approximately 2 litres a day for women and 2.5 litres a day for men, including food.

But scientists say there is actually huge variation in how much each of us need as individuals.

Ruth Alexander speaks to Professor John Speakman at the University of Aberdeen in Scotland, who explains why your age, sex, weight, and other environmental factors such as air temperature, humidity and altitude all make a difference.

Dr Nidia Rodriguez-Sanchez, senior lecturer at the University of Stirling in Scotland, explains why our bodies need water and what happens if we drink too little, or too much.

That happened to Johanna Perry in the UK, she tells Ruth what happened when she drank too much water whilst running the London Marathon in 2018.

Presented by Ruth Alexander.

Produced by Beatrice Pickup.

(Image: a woman holding a plastic bottle of water. Credit: Getty Images/ BBC)

Is it possible to taste a place? A listener wonders whether the French concept of ‘terroir’ can apply to food and, if so, what the science behind it is.

Ruth Alexander goes in search of the answer, exploring how growing conditions and practices can develop flavours unique to a location.

She also hears about why the value you give to certain flavours might also be cultural.

Ruth speaks to a honey expert who is mapping the flavours of the sweet syrup across the world, a barley geneticist working with a high-end whisky brand and visits a vertical farm in Liverpool, UK, to see if foods grown in a closed environment still taste just as good.

If you would like to get in touch with the show, please email: [email protected]

Presenter: Ruth Alexander

Producer: Hannah Bewley

(Image: A barley field under a setting sun. Credit: Getty Images)

Fancy starting a food truck? It can be a way to trial new food concepts and see if your business has potential before committing to a restaurant premises.

Ruth Alexander finds out what its really like running a food truck or van. She meets customers queuing for over an hour for the SpudBros van in Preston, north-west England, where brothers Harley and Jacob Nelson have drummed up business for their jacket potatoes on social media. Ruth speaks to Anna Brand who runs a vegan food van Vege Bang Bang in Auckland New Zealand, and sisters Natalie and Samantha Mwedekeli who started Mama Rocks, a food van selling gourmet burgers in Nairobi, Kenya in 2015.

Today they have five premises and its time to sell the van that started it all. And Karan Malik talks about his food van SuperSuckers in Delhi, India. He saw the trend take off, but tells Ruth why he decided to get out of the business.

If you would like to contact the programme email [email protected].

Presenter: Ruth Alexander

(Image: Brothers Jacob and Harley Nelson in their food van selling jacket potatoes in Preston north-west England. Credit: BBC)

An Indian curry house is one of the most popular places to go out for a meal in the UK, and is part of British life. But many people do not know their origins lie in what is now Bangladesh, after a wave of migration from there in the 1970s.

Devina Gupta traces their history and flavours on Brick Lane in east London, where many people settled and started restaurants. Many have closed over the years, but their legacy lives on. And now more diverse and authentic flavours are becoming popular in the capital and elsewhere.

Presenter: Devina Gupta

(Photo: Brick Lane sign with Bangla language version underneath. Credit: BBC)

Ruth Alexander learns about ‘forever’ foods - stocks, soups and sourdough starters that can be replenished again and again and used for weeks, months or even years.

Ruth hears about a beef soup in Bangkok that has been maintained for 50 years, and she bakes a loaf of sourdough bread using a 69-year-old starter that has been kept going by Hobbs House Bakery in the south-west of England.

Cookbook writer Fuchsia Dunlop in London, UK, talks about the tradition of cooking with an ‘everlasting’ broth in Chinese cuisine.

Annie Ruewerda in New York in the US was charmed by the idea of a perpetual stew, she kept hers going for two months and it became an online hit – bringing hundreds of strangers to her local park to try the stew and add ingredients.

Lee-Ann Jaykus, distinguished professor emeritus and food microbiologist at North Carolina State University in the US explains the food safety rules you need to know if you want to try a perpetual dish at home.

Martha Carlin, distinguished professor of history at the University of Wisconsin-Milwaukee in the US helps unravel the claimed historical origins of perpetual stew.

And our thanks to World Service listeners David Shirley and Mark Wood for telling us about the oldest dishes they have eaten.

Producer: Rumella Dasgupta and Beatrice Pickup

(Photo: A huge pot of beef soup in that has been added to over 50 years at a restaurant in Bangkok, Thailand. Credit: David Shirley/BBC)

Social media is awash with videos of people trying out new recipes at home and exploring the best hidden foodie gems in cities around the world.

The stream of content seems endless – so how do the people making these videos keep up?

Ruth Alexander speaks to three people in the UK, USA and Vietnam about having six meals before 10am, the relentless pressure to keep up with viral trends, and what they cook for themselves when the camera is off.

Tod Inskip, Lylla Nha Vy and Jackie Gebel share the highs and lows of being a “content creator” and why they don’t like the term influencer.

Presenter: Ruth Alexander

Producers: Hannah Bewley and Elisabeth Mahy

If you would like to get in touch with the show, please email: [email protected]

(Image: Lylla Nha Vy, Tod Inskip and Jackie Gebel. Credit: Composite BBC)

If you’re a light or moderate drinker, the World Health Organization wants you to know that no level of alcohol is safe for your health.

But just how big is that risk and might it be one you’re willing to take? And what happened to the idea that a glass of red wine might be good for you?

In this programme Ruth Alexander finds out about the studies the guidance has been based on, and the statistical risk of dying from alcohol-related disease.

Dr Tim Stockwell, Scientist at the Canadian Institute for Substance Use Research, is the author of a meta-analysis of 107 studies that look at the links between ill health and alcohol. Professor Sir David Spiegelhalter is Emeritus Professor of Statistics at the University of Cambridge in the UK, he explains how we can make sense of risk as individuals.

And Anna Tait in the UK, Amelie Hauenstein in Germany, David Matayabas in the US and Bill Quinn in Australia talk about how much alcohol they drink, and what moderation looks like to them.

Presented by Ruth Alexander.

Produced by Beatrice Pickup.

(image: four hands raising pints of beer in a ‘cheers’ gesture. Credit: Getty Images/BBC)

Is it worth taking collagen? With cosmetic companies and A-listers claiming it can slow the effects of ageing, the market for collagen supplements is booming. How sure is the science though?

Ruth Alexander speaks to experts about what we do and don’t know about what these powders, gels and capsules are doing inside our bodies.

She hears from a personal trainer and runner in her 50s about why she takes it daily, and speaks to the CEO of a company selling collagen products in this increasingly competitive market.

New avenues of research are opening up as well, with sports scientists investigating whether an increase in collagen production can help athletes recover from injury more quickly.

If you would like to get in touch with the show, please email: [email protected]

Presenter: Ruth Alexander

Producer: Hannah Bewley

(Image: A serving of supplement powder. Credit: Getty Images)

Have you visited a food hall recently? It’s a venue bringing together multiple independent food and drink businesses, often with communal seating.

We look at the ways in which food halls are being used to bring consumers and spend to new areas, raising the value of surrounding offices, apartments and other businesses.

In this programme Devina Gupta visits Society food hall in Manchester in the UK, where she meets Julia Martinelli, who manages the pizza offering from Noi Quattro restaurant and Reece Gibson, operations manager for Vocation Brewery which runs the bar.

Mariko Oi in Singapore reports from the Maxwell Hawker Centre in Singapore, to explore how today’s food halls have evolved from street food traders.

Frode Rønne Malmo from Mathallen in Oslo, Norway and Spiros Loukopoulos, from Reffen in Copenhagen, Denmark talk about the ways in which their food halls have brought people to the surrounding area. Food hall consultant Philip Colicchio in New York in the US explains why this business model has been so popular.

Presented by Devina Gupta.

Produced by Beatrice Pickup.

Additional reporting by Mariko Oi.

(Image: a man and a woman enjoying plates of food in a food hall. Credit: Getty Images/BBC)

Strawberries at the airport when meeting your future husband for the first time, finally tasting world famous fish and chips and wondering why on earth the pasta is green.

These are some of this week’s stories of first impressions of food in a new country.

Devina Gupta visits a multilingual cooking class in Manchester, UK, to find out how language, culture and food help people find a home in a new part of the world..

She speaks to a chef who fled Ukraine when the war started and now runs a restaurant in the Netherlands. Nathalia adapted to life there very quickly, but still can’t comprehend why the Dutch eat toast for every meal.

Mariyam and Marius share their love story from across continents, and talk about the dishes – and those strawberries - which brought them together when they finally met.

If you would like to get in touch with the show, please email: [email protected]

Presenter: Devina Gupta