June 24, 2024

Ultra-processed food is a big part of the US diet and can make people sick : Shots

Dr. Chris Van Tulleken participated in a month experiment. He ate 80% of his calories from ultra-processed food. He explains what happened in his new book, Ultra-processed people.

Jonny Storey/Chris Van Tulleken

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Jonny Storey/Chris Van Tulleken

Dr. Chris Van Tulleken participated in a month experiment. He ate 80% of his calories from ultra-processed food. He explains what happened in his new book, Ultra-processed people.

Jonny Storey/Chris Van Tulleken

Eating processed food is nothing new. People are pressing bread to make bread for him thousands of years. But in recent years, our food supply has changed, with an increase in the number of ultra-processed products, made with fillers, additives, stabilizers and synthetic ingredients that our grandparents would not have recognized.

Recent analysis by the Access to Nutrition Initiativefinds that about 70% of food products sold in the US are unhealthy — and much of the food can classified as ultra-processed.

So, are we the frogs in the boiling pot, adjusting to the shift towards ultra-processed foods, not realizing that these foods may promote excessive consumption, which may harm us?

Amid the global surge in diet-related diseases, including obesity and Type 2 diabetes, Dr. Chris van Tulleken, author Ultra-processed peoplehe made himself a test subject for a short, one-month experiment.

Van Tulleken, an infectious disease doctor in his mid-40s, swapped his usual healthy diet, full of fruits, vegetables, lean proteins and whole grains, for foods that came mostly from packages, boxes and bottles.

We spoke to Dr. van Tulleken about his book and his research.

This conversation has been edited for length and clarity.

What exactly changed your diet – what did you eat?

I started eating more snack food, so I would have a mid-morning snack. And I went back to eating the kind of cereal I liked as a kid, so I would eat my chocolate covered breakfast cereal. I drank more soda. And I made small swaps, for example, instead of eating nuts as a snack I would eat chips. And then in the evening I had a lot more convenience food, so I was still eating a few vegetables, but I would have microwave lasagna or takeaway fried chicken or pizza.

In total, about 80% of my calories came ultra-processed foods and that is very easy to do. Most bread in the supermarket is ultra-processed, almost all of our breakfast cereals and snack foods are ultra-processed and most of our convenience foods are also ultra-processed.

Note: A classification system used by researchers foods are categorized into one of four categories, from unprocessed and minimally processed, to ultra-processed.

In your book you describe how you managed to gain weight, which is not too surprising given the foods you ate. You also measured what happened to your gut hormones, what did you get and how did you feel?

I got sick very quickly. I felt terrible. I stopped sleeping, developed anxiety and became very happy. I was the pilot patient in a study I am running with colleagues at University College London. We discovered that my gut hormones were affected. So inside all of our bodies we have hormones that tell us when to stop eating. They are very well developed. All animals have them and ultra-processed food affects these hormones. So, at the end of a meal, my hunger hormones would still be sky high.

This sounds very dramatic. Why do you think you were left wanting to eat more, when you ate enough calories?

I think a lot of this food is engineered to drive overconsumption. This food is energy dense. It is full of fat, salt and sugar. So you can consume calories at a much higher rate than when you are eating whole foods. Also, ultra-processed food is often processed into much smaller particles. So it could be absorbed in a different part of the gut than the part that releases the fullness signal. So I suspect you are eating this food faster than your body’s ability to send a signal to the brain saying, ‘I’m done now’.

This fits with the evidence that foods full of refined carbohydrates such as bread, crackers and chips – which is essentially what many ultra-processed foods are – can increase blood sugar and insulin which can stimulate appetite. What’s new here?

There is a very credible scientist, Kevin Hall, in the United States. He ran a clinical trial and found that when people eat an ultra-processed food diet, they eat about 500 calories more per day, compared to people on a whole food diet, eating the same amounts of fat, salt, sugar and fiber. And there is a lot of it epidemiological evidence which shows that it is ultra-processed food that interferes with our body’s ability to say, ‘you know what, I can stop eating now’.

This was a small study, 20 people. Are you investigating this further?

Yes, we were collecting data to get funding for a larger study that we are running now.

Note: Van Tulleken and colleagues were recruit participants to investigate the effects of an ultra-processed versus minimally-processed diet in the United Kingdom The researchers say it will be the longest dietary trial on ultra-processed food and the first to help people reduce their consumption.

If ultra-processed foods had the same effect on everyone, wouldn’t we expect the entire population to get bigger and unhealthy or do people respond differently?

I think there are two groups of adults. Many people will be able to have a relationship with ultra-processed food that is similar to a relationship with alcohol. Many people can enjoy two glasses of wine or a bottle of beer on a Friday night, and that’s fine. They can have that relationship with him. But many people will recognize that their relationship with these food products is much more addictive in nature.

But, as a society, can we really return to whole foods – or diets made up of unprocessed foods?

There is not an entirely clear boundary between traditional food processing and ultra-processed foods. We cut, cook, smoke, pickle, salt, grind, mince – we’ve been doing that for thousands of years and we have to do it. So processing is fine. But, ultra-processing is when food is made in factories. It is wrapped in plastic. There are strange additives that you won’t find in kitchens. And the purpose of food is profit. So, I eat cheese, but I don’t eat processed cheese. I eat butter, but I don’t eat margarine. I eat traditional flour bread, but I don’t eat emulsified, supermarket bread.

Obesity has many causes, some of which are linked to food insecurity. People with the least amount to spend on groceries often buy the processed food with the longest shelf life, because it is affordable. Do you think governments should regulate?

We governments need to start treating these products a bit like tobacco. We need to limit the marketing of these products and we need to change the labeling on the packets. It is the simplest thing to do what is going on in Chile. They put a black hexagon label on the ultra-processed food packages. So governments should not ban it, or tax the food, because it is the only affordable food for many people. But governments can start to warn people that negative health outcomes are strongly associated with it.

Edited for broadcast and web by Jane Greenhalgh.

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