Dr Xand Van Tulleken sets out five evidence-led food rules as 'Con or Cure' returns
Dr Xand Van Tulleken says a few simple rules transformed how he eats — and why. As the new series of Con or Cure probes the science behind popular health claims, the physician outlines five lessons that now guide his food choices, led by one principle: cutting back on ultra-processed foods.
Co-hosting with journalist Ashley John-Baptiste, Van Tulleken says the show reveals striking patterns in the consumer health market. “You start to spot the price point, the claims, the targeting, the subscription model… They all have similar characteristics even if they seem different,” he notes.
He adds that he is often surprised by how little evidence underpins widely accepted nutrition myths. Ultra-processed foods (UPFs) sit at the heart of that conversation. Van Tulleken admits he once believed packets promising “low fat,” “high protein” or “no artificial flavouring” meant a factory-made product could still be good for him.
He and his twin brother, Chris, have spoken publicly about the impact UPFs had on their weight and health, but Xand says it took him longer to change. After making the podcast A Thorough Examination: Addicted to Food, he was convinced by the science, avoided UPFs and lost weight.
That experience underpins his first rule: treat on-pack health claims as a red flag. “Now I won’t really buy anything with a health claim on the packet,” he says, arguing such labels often signal a strong marketing push rather than “real” food. His second rule is to read ingredient lists closely — he checks for long or unfamiliar additives and will even use his phone camera to zoom in when the print is tiny.
A third lesson addresses mixed messages in nutrition headlines. Van Tulleken recalls flipping between warnings about saturated fat, concerns over seed oils, low-carb advocacy and calls to go vegan. “That all fell away,” he says, when he decided to eat non-ultra-processed foods he cooked himself.
The approach, he adds, made daily decisions far simpler. Fourth, he stresses preparation. He is candid that he still struggles with the pull of UPFs and is not perfect — he does have takeaways or chocolate. The moments he finds hardest, he says, are when he hasn’t been able to plan and make food in advance.
Finally, the fifth rule is to stick with what the evidence shows for him: reducing UPFs has been key, and building habits around that goal helps him stay on track. As Con or Cure continues to examine the claims that shape shopping baskets, Van Tulleken’s message is pragmatic rather than purist: focus on minimally processed, home-cooked food where possible, read the small print, and prepare ahead to make the better choice the easier one.