Nature knows best: ultra-processed food is bad for weight loss

Nature knows best: minimally processed foods are better for your health and – surprise, surprise – ultra-processed food is bad for your diet.

This was the headline finding of the recent clinical trial led by researchers at UCL. When given nutritionally matched diets aligned with the Eatwell Guide, participants lost twice as much weight eating minimally processed foods than when they ate ultra-processed foods.

Participants on the minimally processed diet also reported significant improvements both in the number of cravings they experienced and their ability to resist them.

The study authors say that “when observing recommended dietary guidelines, choosing minimally processed foods may be more effective for losing weight”, an insight which “should complement and expand, not displace, current understanding of diet-related health”.

Processing and health outcomes

For anyone paying attention to the science, the results should come as no surprise. In both observational studies and randomised controlled trials, minimally processed diets have consistently led to better health outcomes when compared to ultra-processed diets, even if the drivers of harm associated with the latter remain under investigation.

More than a dozen countries worldwide have begun to promote minimally processed foods in government policy.

Brazil’s dietary guidelines say its citizens should “make minimally processed foods the basis of your diet”, while New Zealand recommends “a diet with more whole, low or minimally processed foods”. Australian public health authorities recommend “fresh and minimally processed foods” and policies that “increase the production and consumption of whole foods”.

The World Health Organization, reflecting the international consensus, says healthy and sustainable diets are “based on a great variety of unprocessed or minimally processed foods, balanced across food groups”.

No such guidance has been voiced by the UK government, but as costs to the NHS from diet-related disease continue to climb, the scientific rationale for doing so looks increasingly compelling. 

This poses both a challenge to food businesses and an opportunity.

Follow the science

Emails obtained by the Soil Association under the Freedom of Information Act show that the Food & Drink Federation (FDF) spent months lobbying government officials, seeking to remove reference to “minimally processed foods” from its guidance to retailers.

With more than 1,800 emails and documents sent between the DHSC and the FDF in just one year , this lobbying appears to have consumed an inordinate amount of time and resource.

The Soil Association encourages the FDF, and the businesses it represents, to take a more progressive stance. Instead of fighting the growing scientific consensus on the benefits of minimally processed diets, companies should be looking to improve the health potential of their portfolios.

This means looking beyond nutrient reformulation to additional factors which might shape health outcomes. The UCL study authors suggest that texture, energy density, eating rate and hyperpalatability could be among the mechanisms driving the different results of the two diets. The ‘ultra-processed’ category is diverse, and products could be improved in different ways.

Companies should also make their processing data publicly available, allowing scientists and policymakers to conduct further research into making food healthier.

The UK government’s Scientific Advisory Committee on Nutrition (SACN) has said this directly, suggesting government should “compel” industry to share data, including data on additives such as emulsifiers and sweeteners, and on the specific processing methods used in manufacturing.

The Soil Association invites the FDF to respond to the SACN by welcoming and endorsing its call for action.

With public concern over ultra-processed foods showing no sign of abating, food and drink companies deserve forward-thinking leadership. This means accepting the science on minimally processed diets and working to improve the health outcomes associated with ultra-processing – a move which is in the long-term interests of both business and the public.

For that to be achieved, an industry-wide commitment to transparency and data is urgently required.

Rob Percival, head of policy, food and health at Soil Association