Processed vs Whole Foods: The Weight Loss Advantage
A new clinical trial published in Nature Medicine (2025) shows that eating Processed vs Whole Foods, minimally processed foods can double weight loss compared with ultra-processed foods, even when both diets meet healthy eating guidelines. However, it is a small and short study, bear in mind that when looking at a ‘diet’ study a good participant size should be over 100 and perhaps a longer term, of around a year.
At Nabo Health, we believe nutrition should be simple with emphasis on wholefoods. This study starts to show proven signs that the way your food is processed makes a real difference to your health and your waistline.
The Study in Brief
For the trial on Processed vs Whole Foods, researchers at University College London recruited 55 adults with overweight BMI. Over two separate 8-week periods, each participant received all meals, snacks, and drinks delivered to their homes.
Minimally Processed Food (MPF) diet: whole, simple foods like porridge oats, grilled chicken with new potatoes, steamed broccoli, baked salmon with rice, and natural yoghurt with berries.
Ultra-Processed Food (UPF) diet: packaged cereals, ready-meal lasagne, sandwiches made with mass-produced bread, flavoured yoghurts, and reformulated “healthy” convenience foods.
Processed vs Whole Foods Food Examples
| Meal/situation | Minimally Processed (MPF) examples | Ultra-Processed (UPF) examples |
| Breakfasts | Overnight oats; porridge from rolled oats; fresh fruit; homemade cooked breakfasts using fresh ingredients and minimal pre-processing. (zoeharcombe.com) | Breakfast cereal bars; packaged cereals; oat bars; industrial breakfast items that include added flavourings or stabilisers. (zoeharcombe.com) |
| Lunch / Dinners | Meals like homemade spaghetti Bolognese; baked/grilled meats (chicken, salmon); steamed/roasted vegetables; brown rice; fresh soups. (zoeharcombe.com) | Ready-meals (e.g. lasagne); pre-made sandwiches; mass-produced breads; processed sauces; packaged side salads with dressings; plant-based alternatives that are processed. (zoeharcombe.com) |
| Snacks / desserts | Plain yoghurt + fresh fruit; nuts; fresh fruit; minimal-ingredient homemade snacks. (zoeharcombe.com) | Flavoured yoghurts with additives; packaged snack bars; processed sweet / savoury snacks. (zoeharcombe.com) |
Both diets matched the UK Eatwell Guide for calories, fibre, fat, sugar, and salt — so the only difference was how processed the foods were.
The Results
Weight loss was twice as high on the MPF diet compared with UPF.
- MPF: −2.06% of body weight (mostly fat loss).
- UPF: −1.05% of body weight.
Metabolic improvements were greater on MPF, including lower triglycerides and reduced cravings.
Some health markers improved equally on both diets showing that general healthy eating guidelines do matter but MPF consistently produced stronger benefits.
Why This Matters
The UPF diet wasn’t typical “junk food” as it included fruit, vegetables, and balanced nutrition. Yet the minimally processed foods still led to greater weight loss and better health outcomes.
This suggests that processing itself may affect satiety, metabolism, and gut health, not just the numbers on a nutrition label.
The Nabo Health View
This research reinforces what we stand for at Nabo Health: that food is most powerful when it’s as close to its natural state as possible.
Simple swaps, like oats instead of packaged cereals, natural yoghurt instead of flavoured yoghurts, or home-prepared meals instead of ready-meals, can make a real difference over time.
Takeaway
Processed vs Whole Foods. Minimally processed foods don’t just meet nutritional needs, they may support your body in ways that promote sustainable weight loss and better overall health.
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