Not all processing is bad. Frozen vegetables, canned beans and plain yogurt are processed and perfectly healthy. “Ultra-processed” refers to something more specific.
What counts as ultra-processed
Under the widely used NOVA classification, ultra-processed foods are industrial formulations made mostly from substances extracted from foods — refined starches, sugars, oils, protein isolates — plus additives such as flavourings, emulsifiers and colourings that you wouldn’t find in a home kitchen. Examples include soft drinks, packaged snacks, many breakfast cereals, flavoured yogurts, mass-produced bread and ready meals.
A quick test: if the ingredient list contains things you wouldn’t cook with, it’s likely ultra-processed.
What the research shows
A 2024 umbrella review in The BMJ, covering studies of nearly 10 million people, found consistent associations between higher ultra-processed food intake and greater risk of cardiovascular death, type 2 diabetes, anxiety and depression, among other outcomes. Most of the evidence is observational, so it shows associations rather than proof of cause.
The strongest causal evidence comes from a 2019 NIH experiment. Twenty adults lived in a research unit and ate an ultra-processed diet for two weeks and a minimally processed diet for two weeks, with meals matched for calories, sugar, fat, fiber and salt on offer. On the ultra-processed diet, people ate about 500 more calories a day and gained weight; on the minimally processed diet, they lost weight.
Why they might cause harm
Researchers think several factors are involved: they’re easy to eat quickly, energy-dense, low in fiber and engineered to be highly palatable. Some additives are being studied for effects on the gut microbiome.
A realistic approach
Few people can cut ultra-processed foods entirely, and you don’t need to. Practical steps:
- Cook simple meals from whole ingredients more often
- Swap sugary drinks for water, sparkling water or unsweetened tea
- Choose plain versions (yogurt, oats) and add your own fruit
- Keep minimally processed snacks to hand: nuts, fruit, cheese
- Read ingredient lists, not just nutrition panels
Small shifts in the foods you eat most often make the biggest difference.