A professor and leading expert on nutrition and gut health has explained exactly what happens to the human body if it only consumes processed foods in its daily calorie intake.
Professor Tim Spector, who is an expert in epidemiology at King's College London, appeared on Michael Mosley's podcast - Just One Thing - to discuss the effects of processed foods on the body.
Professor Spector said: "In the UK, we have the highest intake of ultra processed foods in Europe. And it's not a coincidence that we also have the highest rates of childhood obesity and adult obesity and diabetes and all these consequences.
"It's been estimated costs about 58 billion pounds a year in those associated health costs, but at an individual level.
"I think it's also important to realise that it's not the fat, the sugar, the salt that we thought was the only thing that was important.
"It's the processing is the fact that these are fake foods. They don't contain natural ingredients.
"They contain extracts of natural ingredients put together in a factory looking like edible food substance and added flavourings - and I think the key thing is people don't realise is that the food is also affecting your gut health."
What is an ultra-processed food?
According to the British Heart Foundation, ultra-processed foods typically have five or more ingredients.
They tend to include many additives and ingredients that are not typically used in home cooking, such as preservatives, emulsifiers, sweeteners, and artificial colours and flavours. These foods generally have a long shelf life.
Ultra-processed foods often contain high levels of saturated fat, salt and sugar and when we eat them, we leave less room in our diets for more nutritious foods.
It’s also been suggested that the additives in these foods could be responsible for negative health effects.
Examples of ultra-processed foods
Listed below are examples of ultra-processed foods you may consume regularly:
- Ice cream
- Ham
- Sausages
- Crisps
- Mass-produced bread
- Breakfast cereals
- Biscuits
- Fruit-flavoured yoghurts
- Whisky
- Gin
- Rum
- Instant soups
- Carbonated drinks
What happens if I only consume processed foods for 10 days?
The health experts both took part in an experiment where they only consumed processed foods for 10 days - with Michael discussing the serious consequences it had on his health.
Michael said: "A couple of years ago, I decided to put myself on a junk food diet, and I was gonna do this for two weeks. I had things like frozen meals, going out for burgers and chips and fried chicken, and having unhealthy drinks, like milkshakes and other things.
"Anyway, I managed to put on about three kilos in two weeks and my waist expanded by three centimeters.
"What was really impressive in a bad way was my blood sugar's went back into the diabetic range having been perfectly healthy, and my blood pressure also soared.
"And I also developed these crazy cravings for this stuff and it really lowered my mood."
Professor Spector had a "surrogate sucker" in the form of his son, who as a university student, tended to consume more processed foods than his dad.
Tim's son agreed to sticking to a diet of purely McDonald's and other takeaways for 10 days, and this is what happened.
Professor Spector said: "He said, Yeah, I love to McDonald's for 10 days eating all my meals. That sounds perfect.
"His student friends were very jealous, but it didn't work out quite so well for him. So after four days, he wants to stop. He was feeling rather unwell and he wasn't doing very well academically anyway, but he did even worse at that time.
"Obviously, you know, I was a doctor and a concerned parent as well.
"So, when he came back after four days and said he'd like to give up and I said no way!
"And so that's what we did. And he did carry on, and he actually got less hungry.
"Interestingly, it started to get to him. He did put on weight though, and he looked terrible. The worst thing is he lost. I think it was 30 or 40 per cent of his species in his gut microbiome."
What did the experts find out?
Both Michael and Tim were in agreement that eating processed foods in the majority of your meals can really have a negative affect on your mental and physical health.
Tim said: "This is a great example of what the British public are doing, by eating 57 per cent on average of all their calories through ultra processed foods.
"It's nearly 70 per cent in kids, and that's an average.
"So, when you think many people are eating over 90 per cent of all their calories as ultra-processed foods - they are knocking out their gut microbes.
"They are increasing their appetite, they are lowering their mood - is it really a surprise we're such a sick nation?
"And we encourage it, it being cheap, it being advertised, it being in our schools everywhere.
"So, that's why it's number one on my list of things to avoid in a healthy lifestyle."
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