What’s in the box? Repeated cross-sectional surveys of United Kingdom recipe box healthiness; 2018 & 2023

Recipe boxes, or meal kits, offer pre-portioned ingredients for multiple meals, delivered to, and cooked at home. They are emerging on the food retail market and increasingly popular with an estimated grocery spend c.£1B GBP in 2023, tripled since 2018 [1] . They are marketed as healthy and may have the potential to improve dietary intake. but little or no research has been done on their nutritional profile. The aim is to assess the evolution of recipe box healthiness over time. Data was collected in two cross-sectional online surveys in September 2018 and March 2023. At both time points, all recipe box companies operating were identified and, for those supplying sufficient nutritional information (for energy, total fat, saturated fat, carbohydrate, sugar, protein, salt, and fibre) per 100g or portion, details were extracted. Two internationally recognised standards were used to assess recipe box healthiness: the UK Food Standards Agency (FSA)Traffic Lights labelling guidance (2) and the World Health Organisation (WHO) guidelines for population nutrition (3) (4) . The proportion of recipes that met FSA green colour coded nutrient levels indicating a healthier profile, (low in fat, saturates, sugars and salt, per 100g and per portion), or complied with WHO standards (for energy, fat, saturates, carbohydrate, sugar, protein, salt, and fibre content per portion), were calculated and compared between 2018 and 2023 using z-proportion tests in Python 3.10. After excluding companies with insufficient nutritional information there was a decrease from 9 to 5 companies between 2018 and 2023. The number of recipes captured increased from 132 to 206. Approximately 50% of all recipes met the WHO standard for energy in both surveys (2023, 43-56%; 2018, 43-61%) (p=0.6207). Statistically significant changes in realising nutrient guidelines occurred between surveys. By either metric only 20% (CI 15-26%) of recipes achieved salt targets in 2023: a 30-point reduction from 2018 (p<0.0001). There was a 20% increase in recipes fulfilling WHO carbohydrate guidelines with 63% (CI 56-69%) compared to 43% (CI 35-52%) (p=0.000457) in 2023 and 2018 respectively and relatedly for sugar, 50% (CI 42-59%), from 62% (CI 56-69%), (p-0.028). Across the surveyed recipes, 43% (95% CI 39-46%) of all nutrients achieved FSA green light status in 2023, a smaller proportion than in 2018, 52%, (95% CI 47-56%) (p=0·0001). Similar proportions of nutrients complied with all WHO standards in 2023 and 2018, 40% (CI 37-42%) vs 41% (CI 37-43%) (p=0.744). Most recipe boxes surveyed in 2023 had a poor nutritional profile, that had worsened since 2018. Recipe boxes need an improved nutritional profile, worthy of their 'health-halo', if they are to improve population nutrition. This is the first study to comprehensively analyse the nutritional profile of recipe boxes. A limitation is the lack of nutritional information for some companies.