Older people can substantially cut back on ultra-processed foods without abandoning a familiar, well-balanced way of eating - and doing so is associated with improvements in several important indicators linked to how the body controls appetite and metabolism.
That is the central result of a new paper my colleagues and I published in Clinical Nutrition.
What counts as ultra-processed foods?
Ultra-processed foods are produced using industrial methods and ingredients that are not normally found in home kitchens. They frequently include additives such as emulsifiers, flavourings, colourings and preservatives.
Typical examples are packaged snack foods, ready-to-eat meals and certain processed meats. A growing body of research has associated diets high in ultra-processed foods with worse health outcomes.
Ultra-processed foods in older adults: how the study worked
For this study, my team recruited people in the United States aged 65 and over. Many participants were living with excess weight or had metabolic risk factors, including insulin resistance or raised cholesterol.
Each participant followed two eating patterns that were low in ultra-processed foods, for eight weeks at a time:
- one pattern included lean red meat (pork)
- the other was vegetarian but included milk and eggs
Between the two eight-week periods, there was a two-week break during which participants went back to their usual diets.
In total, 43 people started the dietary intervention and 36 completed the entire study.
Across both low-ultra-processed patterns, ultra-processed foods contributed under 15% of total energy intake. This is a marked reduction compared with the typical US diet, where more than 50% of calories are estimated to come from ultra-processed foods.
Importantly, the menus were designed to be practical for day-to-day life. Participants were not told to cut calories, aim for weight loss or alter their physical activity.
To ensure accurate tracking, we cooked, portioned and supplied every meal and snack. Both diets prioritised minimally processed ingredients and were consistent with the 2020–2025 Dietary Guidelines for Americans (the US Government’s nutrient-based guidance for healthy eating), while delivering similar calorie levels and comparable amounts of key nutrients.
The 2025–2030 Dietary Guidelines for Americans, released on 7 January 2026, explicitly advise eating less ultra-processed food; earlier versions did not address food processing in a specific way.
Because this was a controlled feeding study, we were able - for the first time - to assess what happens when ultra-processed foods are reduced while keeping nutrient targets aligned with recommendations.
What we found
We compared participants’ outcomes on their habitual diets with their responses during each of the two low-ultra-processed diet phases.
When participants ate fewer ultra-processed foods, they spontaneously ate fewer calories and lost weight, including reductions in overall body fat and abdominal body fat.
The changes were not limited to weight loss. Participants also showed:
- improved insulin sensitivity
- more favourable cholesterol profiles
- fewer markers of inflammation
- beneficial shifts in hormones involved in regulating appetite and metabolism
These benefits were broadly similar whether participants followed the pork-containing diet or the vegetarian (milk-and-egg) diet.
Why it matters
For most adults in the United States, ultra-processed foods account for more than half of daily calorie intake. Although these products are convenient and easy to find, long-term observational studies increasingly connect higher ultra-processed food consumption with obesity and chronic conditions that become more common with age, including type 2 diabetes and heart disease.
As older adults represent an expanding proportion of the world’s population, approaches that protect metabolic health may help support healthier ageing.
Many earlier feeding studies investigating ultra-processed foods have not reflected how people typically eat, particularly in the US. In some cases, researchers have contrasted diets made up almost entirely of ultra-processed items with diets containing almost none, which can be far from real life.
Our work sought to mirror everyday eating more closely while still carefully measuring intake. It is the first to demonstrate that, in older adults, a realistic reduction in ultra-processed foods outside a laboratory setting can deliver measurable health improvements beyond weight loss alone.
For older people in particular, better metabolic health can help maintain mobility, independence and quality of life.
Putting it into practice: reducing ultra-processed foods without drastic changes
A practical takeaway is that cutting ultra-processed foods does not necessarily require a rigid “diet”. Small, repeatable swaps - such as choosing plain oats instead of flavoured instant sachets, unsweetened yoghurt with fruit instead of dessert pots, or simple cooked meals over ready-to-heat options - can reduce ultra-processed intake while keeping meals familiar.
It can also help to focus on what to include: vegetables, fruits, beans and lentils, nuts, wholegrains, eggs, dairy foods, fish and unprocessed meats, alongside oils and herbs/spices for flavour. For older adults, prioritising sufficient protein at meals can be particularly important to support muscle function as part of healthy ageing.
What’s still unknown
This was a relatively small study, which reflects how demanding it is to run trials where researchers tightly control what participants eat. It was also not designed to determine whether the metabolic improvements we observed translate into preventing or delaying conditions such as diabetes or heart disease over the long term. Answering that will require larger studies that follow participants for longer.
From a real-world perspective, it is also uncertain whether people can reliably reduce ultra-processed foods in everyday life without structured support - and which approaches make sustained change more achievable. In addition, it remains unclear which features of processing are most relevant to health, such as additives, emulsifiers or extrusion.
Clarifying these issues could guide manufacturers towards foods that remain convenient but are healthier - and help people choose better options more easily.
By Moul Dey, Professor of Nutrition Science, South Dakota State University
This article is republished from The Conversation under a Creative Commons licence. Read the original article.
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