“You can’t outrun a bad diet,” Henry Dimbleby writes in the National Food Strategy, in a discussion of England’s obesity crisis. Dimbleby emphasises that when it comes to obesity and excess weight, diet is more decisive than movement, and the food environment trumps individual knowledge and willpower. This look beyond “calories in/calories out” is astute, but Dimbleby’s proposed solution poses a question. If you can’t outrun a bad diet, can you reformulate your way out of one?

It’s not immediately obvious that Dimbleby intends to pursue a reformulation agenda. In a lucid passage on appetite, he describes the “delicately interwoven feedback loops involving numerous hormones,” which shape satiety and consumption. Ultra-processed foods, as defined by the NOVA classification, are often calorific and low in insoluble fibre, and can disrupt satiety signalling, he observes, prompting us to overeat. [1] Beyond their poor nutritive composition, there is evidence that ultra-processed foods can also negatively affect nutrient bioavailability, digestive kinetics, emotional wellbeing, and microbiome-brain interactions, while displacing healthy fresh foods from our diet, with deleterious consequences for our health. [1,4]

Evidence suggesting that obesity policy should be targeted at ultra-processed foods is progressively emerging, but the National Food Strategy opts for product reformulation. [5] Alongside welcome and necessary actions to increase fresh fruit and veg consumption, the strategy proposes a £3/kg tax on sugar and a £6/kg tax on salt sold for use as ingredients in processed foods. There are solid grounds for action on sugar and salt, and the Soft Drinks Industry Levy (SDIL) provides a precedent for a fiscal approach, but will reformulating ultra-processed foods to remove salt and sugar suffice in improving the national diet? The SDIL provides a telling case study in what might be the limitations of such an approach.

The SDIL has ostensibly been a roaring success. Public Health England data show that soft drinks contained 43.7 million fewer kilograms of sugar in 2019 compared to 2015, an outcome that has rightly been interpreted as vindication of fiscal interventions aimed at improving our diets. But in targeting sugar, the SDIL has inadvertently contributed to increases in the consumption of artificially sweetened drinks. [6,7]

Data from the National Diet and Nutrition Survey indicate that 65% of children aged 18 months to 3 years old are consuming an average of one can of artificially sweetened drink per day (330g/day of “low calorie soft drinks”). [8] There remains a lack of evidence about the long term health impacts, but documented effects of sweetener consumption include (but are not limited to) increased calorie intake and weight gain among infants and children, with disrupted satiety signalling, entrenchment of sweet preferences, and impacts on gut microbiota among potential contributing mechanisms. [8]

We don’t know the full extent to which the SDIL has prompted increased sweetener consumption in this age group. In response to a Freedom of Information request submitted by the Soil Association, Public Health England conceded it is not monitoring the issue. [9] It seems likely, however, that the “sugar free” claims flowing from the SDIL are helping to ingrain consumption patterns inclusive of artificially sweetened drinks. Indeed, PHE is actively encouraging such consumption, with the Change4Life “good choice” logo allocated for use on artificially sweetened products. [8]

This is not to suggest that the SDIL should be scrapped, but its scope should arguably be extended to include sweeteners. As a minimum, health authorities should stop promoting artificially sweetened drinks with problematic additives to children and families as a “good choice.”

Limits of reformulation

Can you reformulate your way out of an ultra-processed diet? It’s doubtful. Infants consuming too many ultra-processed baby foods are denied the flavours and textures of fresh produce—crucial to the development of a mature palate and healthy eating behaviours—even when the product carries a “low salt” or “low sugar” claim. [10] The emulsifiers and additives ubiquitous to ultra-processed foods might diminish the diversity of gut microbiota, even when these products have been reformulated to remove excess calories. [11] The association between ultra-processed foods and depression is unlikely to be resolved by tweaks to product specifications, while consumption of these foods might still prime the microbiome and brain for food addiction, especially among infants. [1,12] Staple foods such as supermarket breads will remain nutritionally depleted—ultra-processing denuding them of beneficial bioactive compounds, vitamins and minerals—in the context of a reformulation agenda targeting sugar and salt.

The proposed tax on sugar and salt should be seen in context. The National Food Strategy outlines a range of actions aimed at improving the food system in England. Several of these actions, such as the “social prescribing” of fruit and vegetables and improvements to public procurement, could help to tip the scales against consumption of ultra-processed products. Dimbleby is also supportive of nature-friendly farming and suggests that diets should be put on a more sustainable trajectory. The government has committed to responding within six months, and our political leaders should be encouraged to implement the strategy, including fiscal measures targeting sugar and salt. These measures are important and progressive, but they will ultimately need bolstering with policies addressing ultra-processed foods more directly.

Other nations are showing the way. The French government has introduced a percentage reduction target for ultra-processed foods in the national diet, while Brazil, Canada, Ecuador, Peru, and Uruguay have adopted dietary guidance targeting these foods. Israel and Chile have introduced on-pack labelling, while the Pan American Health Organization has developed a nutrient profiling model that includes thresholds for artificial sweeteners alongside other nutrients, and health authorities in Philadelphia have included artificially sweetened drinks in their soft drinks tax. [13-15] What these approaches have in common is the recognition that nutrient profiling and NOVA should both play a role in health policy. Action to curtail consumption of ultra-processed foods can, and must, be pursued in tandem with policies targeting “high fat sugar salt” foods. 

This principle holds true in the UK, where the national diet has become skewed from the youngest age, and consumption of ultra-processed foods is higher than any other European country. [16] We too should adopt a percentage reduction target for ultra-processed foods in the diet. We too should explore the potential for ultra-processed food labelling to sit alongside “high fat sugar salt” traffic lights. The National Food Strategy points towards a healthier future. To attain that future, we must look beyond reformulation to grasp the ultra-processed nettle. 

Rob Percival is head of food policy at the Soil Association, where he leads campaigns and advocacy on healthy and sustainable diets.

Competing interests: none declared.

Twitter: @Rob_Percival_

References:

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