Unpacking the Effects: How Ultra-Processed Foods Impact Your Gut
- sandyb79
- Jun 20
- 2 min read
Ultra-processed foods (UPFs) have been getting a lot of attention lately, and for good reason: we’ve known these foods aren’t ideal for health for a while now, however newer studies are beginning to uncover just how extensive the impact might be, with one recent review linking UPF consumption to 32 different health conditions. Although we don’t yet know all the mechanisms behind this, research is pointing towards several possible mechanisms, including effects on the gut microbiota.
What exactly are ultra-processed foods?
UPFs are industrially manufactured products that typically contain ingredients not commonly used in home cooking such as artificial flavours, emulsifiers, sweeteners, colourings, and various food additives. These foods often undergo multiple stages of processing, which alters the structure of their original ingredients. Many UPFs are easy to identify, but others are marketed as healthy options, which can make them harder to spot.
How ultra-processed foods affect digestion and gut health
One of the main issues with UPFs is the level of physical processing that ingredients undergo. Ingredients in UPFs are often broken down extensively during processing, meaning that the body doesn’t have to work to digest these itself. While this might sound efficient, it can result in faster nutrient absorption, higher post-meal blood glucose levels, and reduced satiety (fullness), which may contribute to overeating.
UPFs may also have a negative impact on the gut microbiota, which can have follow-on effects for physical and mental health. When nutrients are absorbed earlier in the digestive process, fewer food substances (especially fibre and complex carbohydrates) reach the colon, which leaves less food for your gut microbes. This can impact production of short-chain fatty acids and other beneficial by-products that help regulate inflammation, appetite, and brain function.
Many UPFs contain cosmetic additives such as emulsifiers, artificial sweeteners, sulphites, and preservatives. Research suggests these substances may negatively impact gut microbiota diversity and composition, reducing the amounts and types of beneficial bacteria, and increasing strains associated with inflammation and chronic disease risk.
UPFs are also typically high in refined sugars and fats, and salt - which have also been shown to negatively influence the gut microbiota, especially when consumed in large amounts over time.
How to spot an ultra-processed food
Recognising UPFs isn’t always straightforward. While some are obvious (soft drinks, packaged snacks), others are marketed as healthier choices, like some muesli bars, soups, and plant-based products. It's also often difficult tell the degree of processing just by looking at a product.
The easiest way to check if a product is likely to be an UPF is to look at the ingredients list: if you spot at least one ingredient that you wouldn’t typically use in your kitchen at home, there’s a high chance it’s ultra-processed, even if the label says “natural.”
Some common ingredients used in ultra-processed foods include:
High fructose corn syrup
Hydrogenated oils
Hydrolysed proteins
Flavour enhancers, artificial flavours or colours
Emulsifiers, thickeners, gelling or bulking agents
Artificial or non-nutritive sweeteners
How to reduce your intake of ultra-processed foods
