One of the UK's leading nutritional experts has called for people to avoid a popular type of food, after branding it 'fake'. Professor Tim Spector was talking on the Exhibit A with Abbey Clancy podcast about what people should eat to maintain a healthy lifestyle.

The professor of genetic epidemiology at King’s College London and founder of the Zoe health app urged people to ignore 'low-calorie', ultra-processed foods. Defined by the British Heart Foundation as foods that 'typically have more than one ingredient that you never or rarely find in a kitchen', they now make up move than 50 per cent of the calories consumed by the average Brit every day.

It makes the UK one of the worst offenders in the world when it comes to consuming ultra-processed foods, but their affordability and convenience means they remain hugely popular. Many are high in fat, sugar or salt, and have been linked with cancer, heart disease, obesity and depression.

Common examples of ultra-processed foods include ice cream, ham, crisps, mass-produced bread, breakfast cereals, fizzy drinks, fruit-flavoured yogurts and instant soups.

Despite their popularity, Prof Spector urged people to avoid anything advertising itself as 'low-calorie', as this would mean it had undergone some form of processing and would be 'fake'. He said: "We should, I think, be completely ignoring calories because they’re misleading. If your calories are made up of ultra-processed food or real food, your body will deal with it in a completely different way.

"It’s the wrong way to look at food. It’s such a crude indicator. Ignoring calories completely is quite liberating for many people and you should actually avoid anything that says it’s low-calorie on the packet because that means it’s fake."

Prof Spector said that 56 per cent of the calories consumed by the average Brit come from ultra-processed foods. In some Southern European countries, it is as low as 15 per cent. Worryingly, around 70 per cent of British children's calories come from ultra-processed foods.

Another problem with ultra-processed foods is that it stops us eating whole foods which are full of the vitamins and nutrients our bodies need to be healthy. Fibre is a prime example.

About 95 per cent of Brits don't eat enough fibre, yet many ultra-processed foods have it stripped out since it can't be easily manipulated, Prof Spector said. He calls ultra-processed foods 'edible food-like substances' which take the ingredients from real food, then strip away key components.

"They take the essential extracts from food and they combine them in different ways," he explained. "They have to add glues, chemicals and additives to stick stuff together and to make it look like food again."