Discussion
This study examined differences in the amount and percentage of products classified as ‘high in’ nutrients of concern among a large sample of packaged foods and beverages available in Peruvian markets following the first phase of the FOPWL policy. Our findings reveal that, in the cross-sectional analysis, the proportion of foods with any ‘high in’ decreased by 6 percentage points, while the proportion of beverages with any ‘high in’ decreased by 11 percentage points compared with the pre-implementation period. Overall, the proportion of products with any ‘high in’ designation reduced from 54% to 47% during the study period. The main reductions were observed in products ‘high in’ sugars, with relative decreases of 10% among foods and 37% among beverages. Notable relative reductions among foods, in the order of 16% and 7%, were also observed in sodium and saturated fats, respectively. The reductions varied by product categories, with the greatest differences observed in groups where the regulatory thresholds were set below the prepolicy 75th percentile of the nutrient distribution—suggesting that the policy incentivised reformulation among products with initially higher nutrient levels. The longitudinal analysis confirmed these trends, reinforcing the finding that Peru’s FOPWL policy has influenced reformulation efforts. These findings support nutrient warning labels as an effective regulatory tool to encourage manufacturers to improve the nutritional quality of packaged foods, potentially contributing to healthier food environments.
Peru was the second country to implement a FOPWL law in Latin America and the first middle-income country in the region to do so. Evidence on the policy’s effect on the food supply was limited. Our study expands on an initial longitudinal study that examined differences 2 years after the policy implementation in nutrients of concern in the top-selling products in Peru, which found a decline in the proportion of ‘high in’ products.20 Both studies found reductions in sugar content and in the proportion of products ‘high in’ sugars. However, while Saavedra-Garcia et al20 found no reduction in the proportion of foods ‘high in’ sodium or saturated fats, both our cross-sectional and longitudinal analyses showed a reduction in foods ‘high in’ both nutrients. Differences may be attributed to variations in product selection and sample size (>1600 longitudinal products in our study vs 94 products in the earlier study).
In addition, our study results align with findings from Chile following the first phase of its FOPWL implementation, with reductions of similar overall magnitude observed in both countries. Cross-sectional analyses showed a 7-percentage-point reduction in the proportion of products with any ‘high in’ designation: from 51% to 44% in Chile13 and from 54% to 47% in Peru. It is important to note key differences between the two policies. While Chile’s regulations require a ‘high in energy’ label, the Peruvian law does not. Conversely, Peru mandates a ‘contains trans fat’ label, which is not required in Chile. Despite these differences, both countries had the largest reductions in products ‘high in’ sugars.13 Given that stricter nutrient thresholds in later implementation phases in Chile led to further reductions,14 similar trends may be expected in Peru, as its policy tightened in the second implementation phase. These results underscore the potential of mandatory labelling policies to drive product reformulation and improve the food supply.12 30 While voluntary systems (eg, Health Star Rating) have also been linked to reformulation,10 mandatory policies are expected to produce more consistent changes across the market.31
Our cross-sectional analyses captured differences in the percentage of ‘high in’ products and nutrients of concern in the food supply, reflecting both reformulation and product turnover (ie, introduction and discontinuation of products). In contrast, the longitudinal analyses provided stronger evidence of reformulation, as they tracked modifications in the same products over time. While both approaches yielded similar results, key differences highlight their complementarity in assessing food supply changes. Both analyses identified reductions in sugar across breakfast cereals and bars, sweet bakery products, sweet spreads, ice creams and sweetened beverages. Reductions in products ‘high in’ sodium were observed in savoury sauces and spreads and in processed meats, fish and seafood, while reductions in saturated fat were detected in ready-to-eat meals, bread and savoury bakery products, savoury sauces and spreads and sweet bakery products, suggesting substantial reformulation. However, reductions in sugar in milk-based drinks and in saturated fat in breakfast cereals and bars were observed only in the longitudinal analysis, possibly reflecting the entry of new high-sugar or high-saturated fat products into the market within these categories during the study period. Conversely, both analyses identified increased saturated fat in dairy-based products, likely due to reformulation favouring full-fat ingredients due to consumer preferences or industry trends. Increases in saturated fat in candies, sweet confectionery, processed fruits and processed meats were observed only in the cross-sectional analysis, suggesting product turnover rather than reformulation.
The most substantial reductions in both analyses were observed in the proportion of products ‘high in’ sugars. A likely contributor is the substitution of sugar with non-sugar sweeteners (NSS) to avoid the FOPWL.32 Unlike policies in Mexico, Argentina and Colombia, Peru’s policy does not require NSS labels, potentially incentivising manufacturers to replace sugar with these sweeteners.15 In Chile, the use of NSS increased following the implementation of its labelling policy, with reformulated products that lowered sugar content being more likely to incorporate NSS.33 Similarly, the proportion of Peru’s top-selling products containing NSS increased from 34.5% in 2019 to 62.1% in 2021.20 In contrast, Mexico’s recent evaluation found that the proportion of products containing NNS actually decreased, highlighting the effects of mandatory NSS labels.15 Further research is needed to assess shifts in the use of NSS across the Peruvian food supply and the potential health implications.
An important regulatory issue arises regarding nutrient labelling in semisolid products, such as ice cream and yoghurts. The thresholds in the Peruvian regulation are based on absolute values, which may have implications if products can shift between solid and liquid categories. For instance, in the case of yoghurts, cross-sectional and longitudinal quantile regression analyses confirmed that these products contain elevated sugar amounts, yet only 4% were labelled as ‘high in’ sugar in the postpolicy cross-sectional sample. This discrepancy stems from how these semisolid products report their unit of measurement. Peruvian regulations allow manufacturers of these products to choose between grams or millilitres, and most declare them in grams, which are subject to the more lenient nutrient thresholds for solids (eg, 22.5 g of sugar per 100 g instead of 6 g per 100 mL for liquids). This regulatory feature enables many semisolid products to avoid warning labels, revealing a loophole that may be exploited to bypass stricter standards. Future revisions of the law should address this inconsistency.
Moreover, trans-fat outcomes were not included in the present analyses due to important limitations in the reliability and interpretability of trans-fat information reported on NFPs during the study period. Although Peruvian regulation mandates the declaration of trans fats and the use of a ‘contains trans fat’ warning label for products containing any amount, there was substantial ambiguity between 2019 and 2021 regarding how trans-fat content should be quantified and reported. Labelling practices were influenced by international standards that allow products containing <0.5 g of trans fat per serving to be declared as ‘0 g’, potentially obscuring the true presence of trans fats.34 This was further reinforced by regulatory decisions in Peru that aligned with these standards,35 contributing to evolving interpretations of the law and inconsistencies in labelling over time. As a result, identical products may have reported different trans-fat values across periods without any reformulation. Together, these factors limit the validity of using NFP data to assess the presence or changes in trans fats in the food supply. While Peru has made important regulatory efforts to reduce industrial trans fats, including the implementation of a Supreme Decree in 2016 mandating their gradual elimination,36 37 current limitations in NFP reporting hinder the ability to monitor compliance and evaluate policy effectiveness, representing a critical regulatory gap. Strengthening requirements for the measurement and reporting of trans fats is essential to support accurate monitoring of the food supply and rigorous policy evaluation.
Reformulation is a key strategy for obesity prevention.30 Consistent with Geoffrey Rose’s concept of population-level prevention,38 our findings suggest that structural policies like FOPWL can promote reformulation and shift the distribution of nutrients of concern across the food supply in a favourable direction (figure 2). While absolute reductions in the percentage of ‘high in’ products may appear modest (6 percentage points–11 percentage points), these differences are substantial in the context of public health. When these leftward shifts in nutrients of concern occur across a wide range of products consumed by millions, they may significantly reduce population-level exposure to diet-related disease risk. Reformulation also reduces reliance on individual behaviour change and may help reduce health disparities by improving the nutritional quality of foods widely consumed by marginalised groups.39
In addition to targeted nutrient reductions, reformulation may also influence energy and nutrient profiles more broadly. For example, products reformulated to reduce sugars or saturated fats may also reduce overall caloric content.40 Conversely, manufacturers may add dietary fibre or increase protein to improve nutritional profiles or maintain product functionality,41 42 which could alter the energy density and overall nutrient composition of products. These reformulation strategies are particularly relevant in regulatory contexts based on absolute nutrient thresholds and may influence the net nutritional quality of the food supply beyond the observed shifts in nutrients of concern but were not captured in our evaluation. Future research should consider assessing additional nutrient substitutions resulting from reformulation to better understand the broader nutritional consequences of mandatory labelling policies.
However, reformulation still has important limitations. Reformulated products may remain highly processed and contain alternative ingredients which do not necessarily contribute to a healthier diet.43 Qualitative studies also show that consumers may perceive UPFs and SSBs without warning labels as inherently healthy, which could lead to unintended consequences.44 Moreover, there is limited long-term evidence on whether reformulation leads to meaningful improvements in dietary intake and health outcomes. These concerns highlight the need for broader food policy strategies that also promote equitable access to fresh, minimally processed foods.45–47
This study is not without limitations. First, because NFPs are not mandatory in Peru, we excluded several products that lacked NFPs or had missing values for undeclared nutrients (~34% of products at T0 and ~30% at T1). This exclusion rate is higher than in countries such as Chile and Mexico, where mandatory labelling policies are in place,48 49 and contributes to a smaller final analytic sample. It is also possible that manufacturers of less healthy products are more likely to omit NFPs, leading to a sample skewed towards relatively healthier options. This limitation underscores the need for policies mandating NFP inclusion on all packaged products in Peru. Second, we did not conduct laboratory analyses and relied on nutrient values reported on labels, which may not always reflect actual content.50 Third, the study focused only on nutrients of concern, without evaluating whether these were replaced with other components such as additives or fibre, which was beyond the study’s scope. Fourth, due to inconsistencies and lack of standardisation in trans-fat reporting during the study period, these values could not be reliably analysed and were therefore excluded. We observed substantial implausible fluctuations in reported trans-fat amounts across years, and consequently, trans fats were excluded from analyses. Finally, we did not assess the impact of the second phase of the FOPWL policy, which introduced stricter thresholds and may have led to further reformulation.
Despite these limitations, this study provides valuable insights into the early effects of Peru’s FOPWL policy. The reductions in nutrients of concern suggest that the policy is driving positive changes in the food supply. Ongoing monitoring is essential to assess long-term compliance and the impact of stricter regulatory thresholds.