From paleo to intermittent fasting: are any diets actually good for us?

Madeleine Finlay sits down with her co-host and Guardian science editor, Ian Sample, to discuss three science stories from the week, including a study that offers a clue in the age-old debate about whether sex differences are present from birth or a product of socialisation. Also on the agenda is the super El Niño, which is predicted to lead to 450,000 deaths in the next six months, and an answer to why the UK’s meningitis outbreak earlier this year was so big.. Help support our independent journalism at theguardian.com/sciencepod

As diet trends proliferate on social media, it can be hard to work out which are backed by science and which should be ignored. From paleo to keto, raw food to intermittent fasting, each attracts a tribe of ardent followers. Now Daniel Lieberman, professor of biological sciences at Harvard University, has written a book to try to cut through the noise. In Fed Up, he uses his background as an evolutionary anthropologist to scrutinise the evidence, turning himself into a guinea pig in the process and trying various diets. In this podcast, he tells Ian Sample which one has remained part of his routine. Help support our independent journalism at theguardian.com/sciencepod

In early September, OpenAI announced it had solved a major mathematics problem that has stumped humans for nearly a century. The news left mathematicians reeling, and many expressed concern over what will be left for humans as AI becomes ever more adept at unravelling complex problems. Now 25 recipients of the Fields medal – often called the Nobel prize for maths – have signed an open letter expressing their fears of a ‘severe misalignment’ between AI companies and their field. To find out how AI is likely to upend maths – and how mathematicians might respond – Ian Sample speaks to Colva Roney-Dougal, professor of pure mathematics at the University of St Andrews. Help support our independent journalism at theguardian.com/sciencepod

Collagen powders, gummies and pills have boomed in popularity in recent years boosted by claims that they smooth wrinkles, promote glossy hair and help with joint pain. Amid the noise it can be hard to figure out whether there’s any actual science behind the promise of looking younger for longer. Luckily Dr Xand van Tulleken has spent the past three years writing Make me well: a quest to understand the confusing world of wellness, and his chapter on collagen dives deep into the evidence. He tells Madeleine Finlay what collagen does in the body, how we can get it without splashing out on expensive supplements, and why getting to the truth behind wellness claims can be so hard. Help support our independent journalism at theguardian.com/sciencepod

In this episode of Science Weekly, recorded in front of an audience at the London podcast festival on 3 September, Ian Sample hears from Michael Safi, the host of the Guardian’s chart-topping podcast about artificial intelligence, Black Box. In series two, Black Box: the chatbots, Michael meets people who have become convinced they have made scientific breakthroughs, cured diseases or invented new technologies using AI chatbots. Ian, Michael and Science Weekly’s co-host Madeleine Finlay explore the phenomenon labelled ‘AI psychosis’ and ask what it reveals about a technology now used by more than a billion people. Help support our independent journalism at theguardian.com/sciencepod

For decades physicists have been puzzling over the enigma of dark matter. We think it makes up 85% of the matter in the universe, but the mysterious substance cannot be seen or detected, and we know about it mainly through observations of the gravitational effects it has on other things. But now scientists believe they may be a step closer to detecting it. Science editor Ian Sample explains to Madeleine Finlay why, if confirmed, the finding could completely transform our understanding of the universe. And Dr Samuel Eriksen, senior research associate at the University of Bristol, and first author of the research paper, explains how the finding has been received in the physics community. Help support our independent journalism at theguardian.com/sciencepod

Who’s more likely to steal sweets from a child? According to science, it’s the rich. A study seemingly confirming our suspicions about the moral behaviour of the wealthy was one of the winners of the 2026 Ig Nobel prizes, which honour research that makes you laugh and then think. Science editor Ian Sample tells Madeleine Finlay what the researchers think could be behind the phenomenon, and they explore some of the other awards, including one for a surprising quality we look for in our friends and another for a biomechanical definition of kissing. Help support our independent journalism at theguardian.com/sciencepod

From the Guardian Investigates team: Across the world, hundreds of people have come to believe they have made extraordinary scientific discoveries with AI chatbots such as ChatGPT, Claude and Gemini. Others say their AI has ‘awakened’ or is leading them to a higher spiritual realm. The Guardian journalist Michael Safi begins investigating a phenomenon labelled ‘AI psychosis’, travelling to the US to meet two people who have been on weird journeys with their chatbots. Help support our independent journalism at theguardian.com/sciencepod

Methane is a potent greenhouse gas that traps more than 80 times as much heat than carbon dioxide over a 20-year period and causes 25% of global heating today. We definitely don’t want this gas spewing needlessly into the atmosphere, but in 2023 that’s exactly what environment editor Damian Carrington found was happening when he reported on 1,000 super-emitting methane leaks across the globe. Now Turkmenistan, the worst country for mega-leaks, has begun to plug them. Damian tells Madeleine Finlay why some experts call stopping leaks the climate ‘emergency brake’ and reveals which countries are still failing to act. Help support our independent journalism at theguardian.com/sciencepod

Ever since the earliest known recording of whale song was made in 1949, researchers have been captivated by the wails, rumbles, clicks, grunts and squeals of their communication. As technology improves, scientists are decoding the intricate patterns that make different species’ vocalisations distinctive. Madeleine Finlay hears from Emma Bryce, a journalist who has spent months investigating human efforts to understand whale song. She explains how this knowledge could help us better protect whales from human-made harms. Credits: 1. Copyright 1978 National Geographic Society and 1977 Capitol Records, Inc. Commentary by Dr Roger Payne 2. Valeria Vergara/Raincoast Conservation Foundation 3. Footage courtesy of Raincoast Conservation Foundation - Obtained for research under SARA permit XMMS 4 2026 4. Video by Amanda Cotton/Project CETI 5. Footage courtesy of Valeria Vergara and GREMM. Obtained for research under SARA permits QUE-MM02-2016 and QUE-LEP-001-2018 6. Project CETI 7. Project CETI. Help support our independent journalism at theguardian.com/sciencepod