I stopped eating these foods seven months ago — it dramatically changed my weight

A new report published in the British Medical Journal links ultra-processed foods (UPFs) to an increased risk of 32 harmful health outcomes.

But long before I read about that report, I decided at the start of 2024 to stop eating UPFs. I also cut out any foods with added sugar (like chocolate, cake or dessert).

I wasn’t really planning to do it for life (I’m still not), I just felt a bit rough and a bit bloated after Christmas (though at no point have I planned, nor will I plan, to cut out alcohol).

But seven months later, I’m still eating a diet with virtually no UPFs in it at all. This puts me very much at odds with a big chunk of the population in the UK and USA, where it’s estimated that 57 percent of daily energy intake for UK adults comes from ultra-processed foods (in teenagers it's even higher, at 66 percent).

In the seven months I’ve been on this new diet (which you can read about in more detail here if you want any tips) I haven’t weighed myself once. I wanted to, I just don’t own weighing scales. But I recently found myself in a house that did have scales, so I jumped on and I was quite shocked by what I saw.

I had lost at least a stone, possibly a stone and a half. I'm vague because I don't weigh myself regularly. But I know I’m around 172cm (5ft 8in) tall and, whenever I have happened to be in a bathroom with scales in it, for the last few years my weight has been pretty consistent at around 11.5st (sometimes closer to 12st and sometimes closer to 11st).

But this time, I weighed 10st. And I really wasn’t expecting that. While I had noticed recently that my clothes fit differently and I had to use new holes on my belts, I was still shocked to have lost that amount of weight. This was especially so considering I've not cut down the amount of food I've eaten, I've just changed the type of food I eat (I also exercise fairly regularly, but I was already doing that before this year).

But, thinking about it now, the weight loss is probably not that surprising. Dr Chris Van Tulleken, an infectious diseases doctor at University College London, a BBC science presenter and a New York Times bestselling author, drastically changed his diet for an experiment so that 80 percent of it was made up of ultra-processed food.

He “gained a huge amount of weight” and told the Zoe Science and Nutrition podcast: "I just ate what I wanted but with 80 percent of my calories coming from ultra-processed food. I gained a huge amount of weight in one month. I gained so much weight that if I'd continued for the whole year, I would've doubled my body weight."

Why can ultra-processed foods make you gain weight?

UPFs often contain high levels of fat, sugar, salt and other additives, so if you have these foods regularly, they can lead to weight gain. For instance, according to Zoe, "a large study found that participants who ate the most ultra-processed foods were 32 percent more likely to have obesity than those who ate the least". This does not mean you can never eat UPFs, it's just healthier to enjoy them once in a while.

What are the ultra-processed foods we eat most of?

Dr Van Tulleken gave this simple one-sentence definition on ultra-processed food on the Zoe podcast: "If it's wrapped in plastic and it contains at least one ingredient that you don't typically find in a domestic kitchen, then it's ultra-processed food." But there are lots of foods that you might not think obviously fall into this category.

Breakfast cereals and granolas: According to research carried out at Queen Mary University of London, some breakfast cereals consist of a third of their weight or more from sugar. Most cereals and granolas you can buy in the supermarket will fall into the UPF category, though you can find those which are less or minimally processed.

Alternative: For breakfast, mix nuts, Greek yoghurt and fruit in a bowl. You can add natural honey to sweeten.

Ready meals: It's estimated that 90 percent of the UK population consumes ready meals. Not all ready meals are UPFs. However, those that are are likely high in salt, sugar, fat and additives.

Alternative: Cook from scratch.

Pre-packaged cakes and biscuits: Mass-produced cakes and biscuits are full of additives, artificial flavourings and preservatives.

Alternative: You can make healthy, sweet bars from scratch at home in minutes. Try mashing bananas, oats and honey together. You can also try variations like adding or swapping peanut butter, adding fruit like blueberries or raspberries, or adding dark chocolate (dark chocolate above 80 percent has far less sugar than your average supermarket bars and chocolate has genuine health benefits). You’ll find masses of recipes for bars like this online and on TikTok.

Pre-packed meat products: The process of preparing meats like this often incorporates nitrites that have been linked to triggering carcinogenic chemicals, and can increase your risk of developing bowel cancer, the fourth most common type in the UK.

Alternative: If you can’t bear the thought of going without meat, try cutting down a bit, or try swapping in more fish.

Vegan meat substitutes: Turning to a plant-based diet has undoubted health benefits but numerous plant-based "meat" products are excessively processed and loaded with additional salt and flavour enhancers.

Alternative: There are plenty of ways to get all the protein you need without eating either meat or meat substitutes.

Ultra-processed cheeses: Cheese delivers protein, calcium and vitamins. It’s also fermented, which Zoe co-founder Tim Spector says has additional health benefits. So it's a good thing to have in your diet! But ultra-processed cheese (for example, the individually-wrapped orange cheese slices or cheese strings) normally hold roughly only about 60 percent of actual cheese, blended with emulsifying agents and other components.

Alternative: Your everyday normal cheese, including cheddar, feta and halloumi, are usually minimally processed — so tuck in!

Flavoured corn chips: While some plain, salted snacks can be non-UPF, many varieties of corn tortilla chips bear little resemblance to natural corn. "Some of these corn chips are more highly processed than others, having been cooked in refined oils with artificial flavours and preservatives added," says dietitian Rhiannon Lambert, author of The Science of Nutrition (DK). If it tastes heavily flavoured, it's best avoided.

Alternative: If you need a snack, nuts are an amazing alternative. You can also try homemade hummus, which is simple and packed with nutrition from chickpeas or beans (depending on which you use).

Flavoured yoghurts: Yoghurt may sound like a healthy option, but many flavoured varieties are so intensively altered and refined that they no longer resemble the natural product.

Alternative: Natural Greek yoghurt is not processed and has no added ingredients at all.

Fizzy drinks: Nearly a quarter of the sugar in our diets comes from sweet drinks like squashes, cordials and fizzy drinks, says Lambert. And diet versions aren't much better. Dr Van Tulleken says simply that they are “terrible for your body".

Alternative: If you’re thirsty, you can’t really go wrong with water. Coffee (while not a thirst-quencher) also has lots of health benefits, which you might find surprising.

Is it hard to cut UPFs from your diet and what are the alternatives?

Before 2024, I probably wasn’t eating an unusually high amount of UPFs when compared to the average diet. The main ways I was consuming them were probably via the granola and flavoured yoghurt I ate for breakfast every morning (thinking it was healthy) and the supermarket bread sandwich with crisps on the side I had for lunch when working at home. The main ways I’ve cut those out while still eating tasty and satisfying meals are:

• eating nuts with Greek yoghurt and fruit for breakfast instead of granola

• adding nuts to salads and other meals too

• cooking more legumes like beans (butter, black, cannellini etc), chickpeas or lentils either as a main or side part of a meal

• eating more vegetables

• making homemade pots of snacks like houmous which I can dip into when peckish

The good thing about having a diet like this is you don't need to stick to it with 100 percent rigidity. In fact, experts say an 80-20 percent balance in favour of non-UPFs is sensible. At the moment, my diet is probably closer to 99-1 percent but that means that if I'm eating out I don't need to worry excessively that the menu might contain certain foods I usually avoid as I've left myself plenty of wriggle room.

Simple recipes with no ultra-processed foods

Here are some really simple and affordable recipes with minimal or no ultra-processed foods:

Jamie Oliver’s Salmon tray bake: this includes stacks of vegetables, salmon and even some healthy Greek yoghurt. See the recipe here.

Vegan chilli: This is made with lots of different kinds of beans. See the recipe here. You can also stir through some roasted sweet potato to bulk it out more and get more meals from it.

Homemade guacamole with sourdough toast: This is simple but epic. Avocados are full of health benefits. All you have to do is mash them up in a bowl to your desired consistency (you can add salt, pepper, chilli or lime juice as you fancy). Fresh sourdough from a bakery tends to have fewer unhealthy ingredients than supermarket-bought bread. Add some eggs on top, and use extra virgin olive oil over the toast instead of butter and you’ll be blown away.

Chickpea or butter bean hummus: Hummus is so easy. Just chuck a few ingredients in a blender. Example recipe here. I find swapping butter beans in for chickpeas makes it softer.

Homemade pesto: As with the hummus above, throw some ingredients in a blender and you're done in seconds. Recipe here.

What health conditions have UPFs been linked to?

A report published in the BMJ attributed UPFs to an increased risk of 32 harmful health outcomes including cancer, diabetes, heart disease and depression.

The research was conducted by a team from Deakin University in Australia and analysed data from almost 10 million individuals across various previously published studies. The findings revealed that those who regularly consumed the highest amounts of UPF had a 21 percent higher risk of premature death and a 50 percent increased risk of dying from heart disease.

There was "convincing" evidence to show that higher UPF intake was associated with:

• 50 percent increased risk of cardiovascular disease-related death;
• 48-53 percent higher risk of anxiety and common mental disorders;
• 12 percent greater risk of type 2 diabetes.

"Highly suggestive" evidence also indicated that higher UPF intake was associated with:

• a 21 percent greater risk of death from any cause;
• a 40-66 percent increased risk of heart disease related death, obesity, type 2 diabetes and sleep problems
• a 22 percent increased risk of depression.
• There was also evidence for associations between UPF and:
• asthma;
• gastrointestinal health;
• some cancers;
• cardiometabolic risk factors, such as high blood fats and low levels of ‘good’ cholesterol.

The researchers cautioned the evidence for this latter group remains limited. The researchers also acknowledged several limitations to the umbrella review, "including that they couldn’t rule out the possibility that other unmeasured factors and variations in assessing UPF intake may have influenced their results", The Guardian reports. Some experts not involved in the research said "much" of the research included in the umbrella review was "weak" and that the findings do not prove cause and effect.

However, Dr van Tulleken said the findings were “entirely consistent” with a now “enormous number of independent studies which clearly link a diet high in UPF to multiple damaging health outcomes including early death”.