Alert – I’m a dietitian who ate ultra-processed food for a month to prove it’s not so bad – the results were shocking

Ultra-processed foods have been linked to everything from obesity to cancer in recent years. 

But Jessica Wilson, a registered dietitian in California, is one of a large group of health experts who thinks the evidence is not so clear-cut.

She and many others argue that ‘ultra-processed’ as a category for food is too broad and doesn’t distinguish between items like bread and sugary sweets, or almond milk and carbonated drinks.

Putting her money where her mouth is (literally), Wilson conducted a month-long experiment to measure the effects of a diet dominated by processed food on her body and mind.

She found eating this way helped give her more energy, helped her stay full for longer, and generally, she said on Instagram, ‘feel a whole hell of a lot better’.

Ms Wilson’s diet for a month consisted of 80 per cent processed foods, like those pictured in the above photo. She said that the category of processed foods is broad, and may include items that many Americans rely on for nutrition

Wilson ate a diet almost entirely of processed foods for a month. These included the many different definitions of ultra-processed – including pre-packaged, frozen meals, takeaway food and foods with more than five ingredients in them. 

Her point, it seems, was in part to prove that the definition for ultra-processed foods is flimsy – so she consumed things like tofu, oat milk and grain-free granola, which may have a number of ingredients but can be considered healthy, as well as familiar favorites such as hot dogs.

‘How can this entire category of foods be something we’re supposed to avoid?’ Ms Wilson told TIME. 

Although the majority of dietitians have come out against processed foods, Ms Wilson isn’t alone in questioning the confusing guidelines in place. 

The most widely recognised way to classify foods is called NOVA. A good rule of thumb is that if your food contains ingredients you don’t recognize or can’t pronounce, it may be processed.

There’s a lot of ‘room for interpretation’ in these guidelines, Carolyn Williams, a registered dietitian, previously told DailyMail.com. 

For example, mass-produced multi-grain bread, may be considered ultra-processed, even though it is a good source of fibre, vitamins and other nutrients that most dietitians would recommend putting into their diet, Ms Williams said. 

It’s clear, she explained, that multigrain bread isn’t in the same category of nutrition as Mountain Dew, which is also highly processed, but lacks nutrients and is high in sugars.

So not all ultra-processed foods are created equal, and therefore might not have the same health effects. 

In order to investigate this gap, Ms Wilson decided to get 80 per cent of her diet from ultra-processed foods for the month of September 2023 – including everything from pizza and hot dogs to vegan cheese, oat milk and grain-free granola. 

The remaining 20 per cent came from vegetables, fruits, eggs, nuts and seeds.

At the end of the month, the dietitian said she felt better, had more energy and wasn’t as hungry as usual while eating mainly processed foods. 

She noted on an recap of the diet that a ‘noticeable gap’ had appeared in the leash she wears around her waist to walk her dog during the month, suggesting she had even lost weight.

These results are likely evidence that she hadn’t been eating enough calories before starting the diet, Ms Wilson said. Eating these pre-packaged foods actually gave her the amount of calories she needed to go about her day with energy, she suggested.  

The NOVA classifying system for processing foods ranks things into four categories based on their ingredients and their manufacturing process. Some dietitians say these guidelines leave room for interpretation 

Still, the popular idea among many dietitians is that processed foods are linked to weight gain and other poor health outcomes.

Processed meats that contain nitrates – a common additive in many sausages and deli meats – have been linked to an increased risk of colorectal and stomach cancer, according to MD Anderson oncologists.

A 2019 study performed by dietitians at the National Institutes of Health fed 20 people a diet of 80 per cent ultra processed foods for two weeks, and a diet of whole foods for two weeks. 

The processed breakfast, for example, might include a bagel and turkey bacon – whereas the unprocessed breakfast might include oatmeal and fruit. 

At the end of the study, the researchers found that when on the processed plan, people ate an average of 500 more calories than on a whole food diet, and gained weight as a result. 

In one of the most widely known studies on processed foods, Dr Chris van Tulleken, a virologist and professor at the University College London, ate an 80 per cent diet of processed foods for a month. 

At the end, he had gained weight, become constipated and said scans showed concerning changes to his hormone levels and brain biology. ‘In just a few weeks, I felt like I’d aged ten years. I was aching, exhausted, miserable and angry,’ Dr van Tulleken wrote in a column for DailyMail.com. 

Ms Wilson said that it’s possible for both Mr Van Tulleken’s study and hers to be true. 

In her eyes, it’s important to consider that there are many ways to use processed foods, and that making them seem all bad makes it harder for people to get the cost-effective nutrition that some processed foods afford. 

She said: ‘Both experiences are real. The public deserves to hear more than one version of a story.’