Are ultra-processed foods linked to cancer?

Are they bad for us?

Many ultra-processed foods, like crisps and biscuits, are high in sugar, salt and saturated fats, and it’s clear that eating too many of these types of foods is bad for us. It can result in weight gain and also leaves less room in our diet for more nutrient dense and fibre-rich foods like fruits, vegetables and whole grains. That’s important because a healthy diet isn’t just about calories, it’s also about making sure we are consuming foods with a range of vitamins and minerals which help our body to function. 

So we know that basing our diet with lots of ultra-processed foods high in fat, sugar and salt would be bad for us. But more research is needed to understand whether there’s a specific negative effect from ultra-processing itself.  

Do ultra-processed foods cause cancer?

Recently, some studies have claimed that eating a diet high in ultra-processed foods can raise people’s risk of cancer and other chronic diseases.  

In one recent review, researchers looked at 45 studies on ultra-processed food exposure and health outcomes. When analysed together, these studies suggested there was a very small increased risk of cancer. But most of them only offered very low-quality evidence for their claims. So currently, the evidence that ultra-processed foods cause cancer is still very weak. 

That means we should take big statements about ultra-processed foods with a pinch of salt. 

Overall, it’s very hard to prove direct links between specific foods and health outcomes. That’s because we don’t just eat one type of food. Our diets are made up of many different things, so it’s hard to determine how a certain food or ingredient is impacting our health. 

Even if we can’t find direct links, that doesn’t mean there couldn’t be an indirect link. As mentioned earlier, ultra-processed foods are often high in salt, sugar and saturated fats. Eating too much of those ingredients can lead to weight gain. We know for sure that being overweight and obese increases the risk of 13 different types of cancer.  

So, it could be that any risk from ultra-processed foods comes from the fact they contribute to obesity, which in turn contributes to cancer risk. That could be separate from the way these foods are processed or the preservatives or additives they contain. In fact, some ultra-processed foods – like wholegrain bread, cereals, or low-fat yoghurts – could even have nutritional benefits. 

Why should we be aware of ultra-processed foods?

The low quality of evidence means it’s too early to say we should be cutting out ultra-processed foods. But if you eat a lot of ultra-processed foods that are high in salt, sugar and saturated fats, it’s a good idea to try and cut down. Reading food labels can help you work out which foods these are and make the best choice for you. You could also think about whether you can make any healthier swaps to help balance your diet, like including more fruit and vegetables or planning home cooked meals. 

Remember, when it comes to cancer risk, the most important thing is to aim for a healthy, balanced diet. That will probably always contain the occasional less healthy or ultra-processed food, but as long as you’re eating lots of wholegrains, fruits and vegetables and keeping a healthy weight, there’s no need to worry.