Comparing Prices for Food and Diet Research: The Metric Matters

Changes in UK price disparities between healthy and less healthy foods over 10 years: An updated analysis with insights in the context of inflationary increases in the cost-of-living from 2021

Food prices and affordability play an important role in influencing dietary choices, which in turn have implications for public health. With inflationary increases in the cost-of-living in the UK since 2021, understanding the dynamics of food prices becomes increasingly important. In this longitudinal study, we aimed to examine changes in food prices from 2013 to 2023 by food group and by food healthiness. We established a dataset spanning the years 2013-2023 by combining price data from the UK Consumer Price Index for food and beverage items with nutrient and food data from the UK nutrient databank and UK Department of Health & Social Care's National Diet and Nutrition Survey data. We calculated the price (£/100 kcal) for each food item by year as well as before and during the period of inflationary pressure, and classified items into food groups according to the UK Eatwell Guide and as either "more healthy" or "less healthy" using the UK nutrient profiling score model. In 2023, bread, rice, potatoes and pasta was cheapest (£0.12/100 kcal) and fruit and vegetables most expensive (£1.01/100 kcal). Less healthy food was cheaper than more healthy food (£0.33/100 kcal versus £0.81/100 kcal). Before the inflationary pressure period (from 2013 to late 2021), the price of foods decreased by 3%. After this period, the price of food increased by 22%: relative increases were highest in the food group milk and dairy food (31%) and less healthy category (26%). While healthier foods saw smaller relative price increases since 2021, they remain more expensive, potentially exacerbating dietary inequalities. Policy responses should ensure food affordability and mitigate price disparities via, for example, healthy food subsidies.

Costing recommended (healthy) and current (unhealthy) diets in urban and inner regional areas of Australia using remote price collection methods

OBJECTIVE

To compare the cost and affordability of two fortnightly diets (representing the national guidelines and current consumption) across areas containing Australia's major supermarkets.

DESIGN

The Healthy Diets Australian Standardised Affordability and Pricing protocol was used.

SETTING

Price data were collected online and via phone calls in fifty-one urban and inner regional locations across Australia.

PARTICIPANTS

Not applicable.

RESULTS

Healthy diets were consistently less expensive than current (unhealthy) diets. Nonetheless, healthy diets would cost 25-26 % of the disposable income for low-income households and 30-31 % of the poverty line. Differences in gross incomes (the most available income metric which overrepresents disposable income) drove national variations in diet affordability (from 14 % of the median gross household incomes in the Australian Capital Territory and Northern Territory to 25 % of the median gross household income in Tasmania).

CONCLUSIONS

In Australian cities and regional areas with major supermarkets, access to affordable diets remains problematic for families receiving low incomes. These findings are likely to be exacerbated in outer regional and remote areas (not included in this study). To make healthy diets economically appealing, policies that reduce the (absolute and relative) costs of healthy diets and increase the incomes of Australians living in poverty are required.

Price Trends of Healthy and Less Healthy Foods and Beverages in Mexico from 2011-2018

BACKGROUND

Cost is one of the main drivers of food selection; thus it is important to monitor food prices. Evidence from low- and middle-income countries such as Mexico is limited.

OBJECTIVE

The aim of this study was to evaluate the prices and price trends of healthy and less healthy food/beverage groups in Mexico from 2011 to 2018.

DESIGN

This study used a time series of the prices of foods and beverages classified by 1) healthiness, 2) processing level, and 3) pairs of healthy/less healthy substitutes.

SETTING

Food and beverage prices used to estimate the Consumer Price Index were obtained. Prices were collected weekly from 46 cities (>20,000 habitants) distributed across the country.

MAIN OUTCOME MEASURES

Price trend (% change/year) from 2011 to 2018 for all food/beverage groups and price/100 g in 2018 for pairs of healthy/less healthy substitutes were obtained.

STATISTICAL ANALYSES

Linear regression models were used for each food/beverage group, with the logarithm of deflated price as the dependent variable and time (years) as the independent variable.

RESULTS

On average, prices for less healthy foods and beverages increased more than prices of healthy foods and beverages (foods: 1.72% vs 0.70% change/year; beverages: 1.61% vs -0.19% change/year). The price change was similar for unprocessed/minimally processed foods and ultraprocessed foods (1.95% vs 1.85% change/year); however, within each processing category, the price of less healthy foods increased more. By pairs of substitutes (within food/beverage groups), the healthier option for bread, sodas, and poultry was more expensive (price/100 g) in 2018, whereas for red meat, cheese, mayonnaise, and milk, the healthier option was cheaper.

CONCLUSIONS

Overall, the food prices of less healthy foods and beverages increased more than the food prices of healthy foods and beverages. However, by processing level there was no difference, and for pairs of healthy/less healthy substitutes results were mixed. Continued monitoring of food prices is warranted, and future research is needed to understand how these price changes affect dietary quality.

How to Estimate Food Prices and Diet Costs in Population-Based Studies?

Health and nutrition surveys usually comprise detailed information on health characteristics and food consumption of certain population groups; however, the lack of data collection on the food prices may pose challenges for the estimation of the diet costs for the comprehensive analysis of food demand. The Household Budget Survey (HBS) represents an opportunity to obtain the data on the food prices for the nutrition surveys in the diverse countries worldwide. Although the HBS and the health and nutrition surveys may correspond to different periods, the application of the appropriate Consumer Price Index (CPI) allows to address the changes in the relative prices to perform the linkage between the data of food consumption with information on the food prices. Therefore, the aim of this study was to present the methods for the extraction and linkage of the food prices data from the Brazilian HBS (2002–2003 and 2008–2009) by using the pairing features related to the household characteristics to match the Health Survey of São Paulo [Inquérito de Saúde de São Paulo (ISA-Capital)] conducted in 2003, 2008, and 2015. Data referring to the household characteristics and food prices acquired by the household members living in São Paulo municipality were selected from the HBS datasets for integration with the ISA-Capital dataset. Specific deflators referring to the food items surveyed in São Paulo were obtained from the datasets of the Brazilian Broad Consumer Price Index (BCPI). Therefore, the pairing criteria referring to time, location, and household characteristics were adopted to allow linking foods consumed by the individuals in the ISA-Capital with the prices from the foods acquired by household members interviewed in the HBS. Matching data on the key pairing criteria (location/year/household income per capita/number of residents/family profile) resulted in the linkage of 94.4% (2003), 92.6% (2008), and 81.2% of the cases (2015). Following the data linkage, it was possible to estimate diet costs per gram and per calorie including application of cooking and conversion factors. Data were presented in the International Monetary Unit under the purchasing power parity (PPP) to allow the comparison at the international level. The mean diet costs identified in the population of São Paulo municipality were $8.45 (dp = 0.38) per capita per day in 2003, $8.72 (dp = 0.24) per capita per day in 2008, and $9.62 (dp = 0.23) per capita per day in 2015. Thus, it was possible to estimate the diet costs based on the prices of food items through pairing linkage of information from the household surveys, such as the Brazilian HBS, with the health and nutrition surveys lacking information on the expenditures or prices such as the ISA-Capital. Similar procedures may be used in the diverse countries with availability of the datasets of the household expenditures and health and nutrition surveys, allowing the researchers worldwide to associate the diet quality with food demand.

Food environment solutions for childhood obesity in Latin America and among Latinos living in the United States

The food environment is a major contributor to unhealthy diets in children and, therefore, to the increasing rates of obesity. Acclaimed by scholars across the world, Latin American countries have been leaders in implementing policies that target different aspects of the food environment. Evidence on the nature and to what extent children are exposed and respond to unhealthy food environments in the region and among Latinos in the United States is, however, deficient. The objective of this review is to use the integrated International Network for Food and Obesity/noncommunicable diseases (NCDs) Research, Monitoring and Action Support (INFORMAS) framework to create healthy food environment to (i) compare the key elements of childhood obesity-related food environments in Latin America and for Latinos living in the United States; (ii) describe the evidence on solutions to improve childhood obesity-related food environments; and (iii) identify research priorities to inform solutions to fight childhood obesity in these populations. We found that an integrated body of evidence is needed to inform an optimal package of policies to improve food environments to which children in Latin America and Latino children in the United States are exposed and more efficiently translate policy solutions to help curb growing childhood obesity levels across borders.

Eggs as an affordable source of nutrients for adults and children living in food-insecure environments

Food insecurity affects an estimated 12% of households in the United States. Adults and children who experience food insecurity are increased risk for development of metabolic diseases such as type 2 diabetes, obesity, and cardiovascular disease. The negative health outcomes associated with food insecurity are multifactorial; however, many of them may be caused by limited nutritional intake and poor diet quality. Dietary intake of eggs may be an applicable solution for food-insecure families who are challenged by limited nutritional intake. Eggs contain a variety of nutrients that support metabolic health. For instance, eggs are a complete source of high-quality protein and contain 16 vitamins and minerals. Furthermore, eggs are cost efficient. When comparing the relationship between foods on the basis of calories and unit cost, the energy cost of eggs is significantly less when compared with that of other animal-protein foods such as meat, poultry, and fish. However, dietary intake of eggs is controversial in regard to cardiovascular health. Thus, the aim of this review is to summarize the role of eggs in the diet and the impact eggs have on health for adults and children living in a food-insecure environment.

Dietary Approaches to Stop Hypertension (DASH) diet and associated socio-economic inequalities in the UK

The Dietary Approaches to Stop Hypertension (DASH) diet is an effective measure in the prevention and treatment of CVD. We evaluated recent trends in socio-economic differences in the DASH score in the UK population, using education, occupation and income as proxies of socio-economic position (SEP). We analysed data on 6416 subjects aged 18 years and older collected in the National Diet and Nutrition Survey (2008-2016). The DASH score was calculated using sex-specific quintiles of DASH items. Multiple linear regression and quantile regression models were used to evaluate the trend in DASH score according to SEP. The mean DASH score was 24 (sd 5). The estimated mean difference between people with no qualification and those having the highest level of education was -3·61 (95 % CI -4·00, -3·22) points. The mean difference between subjects engaged in routine occupations and those engaged in high managerial and professional occupations was -3·41 (95 % CI -3·89, -2·93) points and for those in the first fifth and last fifth of the household income distribution was -2·71 (95 % CI -3·15, -2·28) points. DASH score improved over time, and no significant differences in the trend were observed across SEP. The widest socio-economic differences emerged for consumption of fruit, vegetables, whole grains, nuts, seeds and legumes. Despite an overall increase in the DASH score, a persisting SEP gap was observed. This is an important limiting factor in reducing the high socio-economic inequality in CVD observed in the UK.

Energy intake from unhealthy snack food/beverage among 12-23-month-old children in urban Nepal

Unhealthy snack food and beverage (USFB) consumption among young children has been noted in many low‐income and middle‐income countries (LMIC), however, there is a lack of information on the contribution of these foods to children's diets in these contexts. This study describes the nutrient profiles and costs of snacks consumed by young children in Kathmandu Valley, Nepal, and assesses the proportion of total energy intake from nonbreastmilk foods (%TEI‐NBF) contributed by USFB and factors associated with high USFB consumption. A cross‐sectional survey was conducted among 745 randomly sampled primary caregivers of children aged 12–23 months. Of 239 unique snack foods and beverages consumed, 180 (75.3%) were classified as unhealthy based on nutrient profiling, with 158 of these being commercially branded. Median cost/100 kcal of USFB was lower as compared with healthy snacks. Ninety‐one percent of children had consumed a USFB in the previous 24 hr, with these foods contributing a mean %TEI‐NBF of 24.5 ± 0.7 among all children. Biscuits (10.8%), candy/chocolate (3.5%), and savoury snacks (3.4%) provided the largest %TEI‐NBF. Children who were older, female, or from the poorest households had significantly higher odds of high USFB consumption, whereas children whose caregivers were of upper caste/ethnicity or had achieved tertiary education had lower odds of consumption than other children. To reduce USFB consumption, interventions should seek to further understand social/cultural drivers of feeding practices, target disadvantaged populations, and ensure caregivers are fully aware of the nutritional quality of food products they choose for their children.

Nutrient profiling and food prices: what is the cost of choosing healthier products?

BACKGROUND

The Health Star Rating (HSR) is a front-of-pack label designed to help Australian consumers identify healthier packaged foods. Price is an important determinant of food choice and yet no previous studies have examined the relationship between HSR and price. In the present study, we investigated whether (i) healthier packaged food products, as determined by HSR, are more expensive than less healthy alternatives and (ii) products displaying the HSR are more expensive than similar products that do not.

METHODS

Prices of three packaged foods categories (breakfast cereals, cereal-based bars and fruit juices) and nutrient data (to calculate HSR) were obtained from shopping receipts of approximately 1600 Australians between June 2014 and September 2016. Associations between HSR and price [per energy ($/100 kJ) and per unit ($/100 g)] for products of comparable package sizes were assessed by linear regression and the results are presented as differences in average price over the theoretical maximum range of HSR from 0.5 to 5 stars.

RESULTS

The HSR of products was not consistently related to price. Small positive associations were observed for juice ($0.08/100 mL; P = 0.03) and for cereal-based bars ($0.04/100 kJ; P = 0.02). No other associations between HSR and price were observed (P ≥ 0.23). Products that displayed the HSR were no more expensive on average than products that received a similar HSR but did not display the HSR (P ≥ 0.16).

CONCLUSIONS

In summary, the findings of the present study suggest that healthier packaged food products were not consistently more expensive than less healthy products and also that price is unlikely to be a barrier for consumers to use the HSR to select healthier packaged foods.

Socioeconomic and ethnic differences in the relation between dietary costs and dietary quality: the HELIUS study

BACKGROUND

Healthier dietary patterns are generally more costly than less healthy patterns, but dietary costs may be more important for dietary quality in lower educated and ethnic minority groups. The aim of this study was to investigate the association between dietary costs and dietary quality and interactions with ethnicity and socioeconomic position (SEP).

METHODS

We used cross-sectional data from 4717 Dutch, Surinamese, Turkish and Moroccan origin participants of the multi-ethnic HELIUS study (the Netherlands), who completed an ethnic-specific food frequency questionnaire (FFQ). The primary outcome measure was dietary quality according to adherence to the Dutch Healthy Diet index 2015 (DHD15-index, range 0-130). Individual dietary costs (the monetary value attached to consumed diets in Euros) were estimated by merging a food price variable with the FFQ nutrient composition database. Regression analyses were used to examine main and interaction effects. Analyses were adjusted for age, sex, smoking, energy intake, physical activity, ethnicity and educational level.

RESULTS

Having higher dietary costs was associated with higher dietary quality. Analyses stratified by educational level showed that associations were stronger in higher educated (Btertile3 = 8.06, 95%CI = 5.63; 10.48) than in lower educated participants (Btertile3 = 5.09, 95%CI = 2.74; 7.44). Stratification by ethnic origin showed strongest associations in Turkish participants (Btertile2 = 9.31, 95%CI = 5.96; 12.65) and weakest associations in Moroccan participants (Btertile3 = 4.29, 95%CI = 0.58; 8.01). Regardless of their level of education, Turkish and Moroccan individuals consumed higher quality diets at the lowest cost than Dutch participants.

CONCLUSIONS

The importance of dietary costs for dietary quality differs between socioeconomic and ethnic subgroups. Increasing individual food budgets or decreasing food prices may be effective for the promotion of healthy diets, but differential effects across socioeconomic and ethnic subgroups may be expected.

Meeting UK dietary recommendations is associated with higher estimated consumer food costs: an analysis using the National Diet and Nutrition Survey and consumer expenditure data, 2008-2012

OBJECTIVE

To test whether diets achieving recommendations from the UK's Scientific Advisory Committee on Nutrition (SACN) were associated with higher monetary costs in a nationally representative sample of UK adults.

DESIGN

A cross-sectional study linking 4 d diet diaries in the National Diet and Nutrition Survey (NDNS) to contemporaneous food price data from a market research firm. The monetary cost of diets was assessed in relation to whether or not they met eight food- and nutrient-based recommendations from SACN. Regression models adjusted for potential confounding factors. The primary outcome measure was individual dietary cost per day and per 2000 kcal (8368 kJ).

SETTING

UK.

SUBJECTS

Adults (n 2045) sampled between 2008 and 2012 in the NDNS.

RESULTS

On an isoenergetic basis, diets that met the recommendations for fruit and vegetables, oily fish, non-milk extrinsic sugars, fat, saturated fat and salt were estimated to be between 3 and 17 % more expensive. Diets meeting the recommendation for red and processed meats were 4 % less expensive, while meeting the recommendation for fibre was cost-neutral. Meeting multiple targets was also associated with higher costs; on average, diets meeting six or more SACN recommendations were estimated to be 29 % more costly than isoenergetic diets that met no recommendations.

CONCLUSIONS

Food costs may be a population-level barrier limiting the adoption of dietary recommendations in the UK. Future research should focus on identifying systems- and individual-level strategies to enable consumers achieve dietary recommendations without increasing food costs. Such strategies may improve the uptake of healthy eating in the population.

Mortality, greenhouse gas emissions and consumer cost impacts of combined diet and physical activity scenarios: a health impact assessment study

OBJECTIVE

To quantify changes in mortality, greenhouse gas (GHG) emissions and consumer costs for physical activity and diet scenarios.

DESIGN

For the physical activity scenarios, all car trips from <1 to <8 miles long were progressively replaced with cycling. For the diet scenarios, the study population was assumed to increase fruit and vegetable (F&V) consumption by 1-5 portions of F&V per day, or to eat at least 5 portions per day. Health effects were modelled with the comparative risk assessment method. Consumer costs were based on fuel cost savings and average costs of F&V, and GHG emissions to fuel usage and F&V production.

SETTING

Working age population for England.

PARTICIPANTS

Data from the Health Survey for England, National Travel Survey and National Diet and Nutrition Survey.

PRIMARY OUTCOMES MEASURED

Changes in premature deaths, consumer costs and GHG emissions stratified by age, gender and socioeconomic status (SES).

RESULTS

Premature deaths were reduced by between 75 and 7648 cases per year for the physical activity scenarios, and 3255 and 6187 cases per year for the diet scenarios. Mortality reductions were greater among people of medium and high SES in the physical activity scenarios, whereas people with lower SES benefited more in the diet scenarios. Similarly, transport fuel costs fell more for people of high SES, whereas diet costs increased most for the lowest SES group. Net GHG emissions decreased by between 0.2 and 10.6 million tons of carbon dioxide equivalent (MtCO₂e) per year for the physical activity scenarios and increased by between 1.3 and 6.3 MtCO₂e/year for the diet scenarios.

CONCLUSIONS

Increasing F&V consumption offers the potential for large health benefits and reduces health inequalities. Replacing short car trips with cycling offers the potential for net benefits for health, GHG emissions and consumer costs.