The five food rules one doctor used to reduce UPFs from his diet

On BBC's Con or Cure, Dr Xand Van Tulleken investigates popular health-related claims with journalist Ashley John-Baptiste.

"One of the things I love most about Con or Cure is, we start to see patterns emerge in health myths," says Xand.

"With consumer health products, you start to spot the price point, the claims, the targeting, the subscription model… They all have similar characteristics even if they seem different."

On the show Xand is often surprised by the science (or lack of it) behind widely accepted health myths.

And there are plenty of myths (and emotions) surrounding ultra-processed foods (UPFs).

From marketing claims about how nutritious they can be, to the guilt felt by shoppers when they buy them.

For Xand, it was following the science that turned him away from a diet that was high in UPFs.

Here are five truths that have changed how he eats and thinks about food.

"A myth I once believed was that you can buy ultra-processed food that is made in a factory with lots of ingredients and it can still be good for you. That's because on the packet it'll say things like 'low in fat' or 'high in protein' or 'no artificial flavouring'."

Xand and his twin brother Chris have been very vocal about the impact ultra-processed foods have had on their weight and health. But it took Xand longer to come around to the idea of avoiding UPFs.

Chris had declared he no longer wanted them in his life. Then, when the two started the podcast A Thorough Examination: Addicted to Food, Xand became convinced by the science. He avoided UPFs and lost weight.

"Now I won't really buy anything with a health claim on the packet. These labels very strongly suggest that a marketing team has been involved in selling it to me and I'm likely not buying it because it's 'real' food."

To help work out if something is a UPF, he looks out for unfamiliar ingredients.

"I always read the ingredients on the packet to the point where sometimes, when they're in really small print, I have to use my phone camera to zoom in on them."

"Core messages about what's good and bad for you can seem muddled. I'd see a headline saying that saturated fat is bad, another that said the problem was seed oils. Then perhaps one telling me that I should be following a low-carb diet and another that veganism is important. It was endless.

"That all fell away when I decided I was only going to eat non-ultra-processed foods that I've made myself. That makes things far more straightforward."

"Like many people, I struggle with [the temptation of UPFs] enormously. It's not like I never have a takeaway or a bar of chocolate – I'm certainly not perfect!

"Almost always, the times when I struggle are when I've not been able to prepare and make food in advance."

"If over the weekend I've managed to batch cook meals and snacks, then that really makes a difference. Likewise, if I make sure I've got my water bottle with me, then I'm not having to go into a shop, so I'm not as tempted."

"I would say to anyone struggling with what they're eating: it's not your fault.

"This food that surrounds us, it's terribly unhealthy and is very aggressively marketed. The current food environment makes it very hard for people to take control of their lives.

"I'm very lucky that I have the time and ability to prep some food. But for loads of people, that isn't the case.

"I don't want to tell anyone what they should do because most of us are just living in this terrible food environment, having a hard time."

"The way the diet industry and social media work is that there needs to be a high rate of new claims, which you won't have time to debunk and can spread rapidly. They're only exciting if they're new."

This turns social media into a hotbed of new and seemingly magic solutions for health and weight management, often fuelled by people hungry for clicks and views.

"On the show, we emphasise that you cannot get your health information from social media in a way that will truly help you. Social media needs to deliver a quick-fix culture and it can't give you high-quality information that is good for you or tailored to your needs."

Originally published April 2025. Updated March 2026.

Want more? Visit BBC Food on Instagram, external, Facebook, external and Pinterest, external or watch the latest Food TV programmes on BBC iPlayer.