Modelling the cost differential between healthy and current diets: the New Zealand case study

Differences in the cost and environmental impact between the current diet in Brazil and healthy and sustainable diets: a modeling study

BACKGROUND

While healthy and sustainable diets benefit human and planetary health, their monetary cost has a direct impact on consumer food choices. This study aimed to identify the cost and environmental impact of the current Brazilian diet (CBD) and compare it with healthy and sustainable diets.

METHODS

Data from the Brazilian Household Budget Survey 2017/18 and the Footprints of Foods and Culinary Preparations Consumed in Brazil database were used for a modeling study comparing the cost of healthy and sustainable diets (based on the Brazilian Dietary Guidelines (BDG) diet and the EAT-Lancet diet) versus the CBD. The DIETCOST program generated multiple food baskets for each scenario (Montecarlo simulations). Nutritional quality, cost, and environmental impact measures (carbon footprint (CF) and water footprint (WF)) were estimated for all diets and compared by ANOVA. Simple linear regressions used standardized environmental impacts measures to estimate differentials in costs and environmental impacts among diets scenarios.

RESULTS

We observed significant differences in costs/1000 kcal. The BDG diet was cheaper (BRL$4.9 (95%IC:4.8;4.9) ≈ USD$1.5) than the CBD (BRL$5.6 (95%IC:5.6;5.7) ≈ USD$1.8) and the EAT-Lancet diet (BRL$6.1 (95%IC:6.0;6.1) ≈ USD$1.9). Ultra-processed foods (UPF) and red meat contributed the most to the CBD cost/1000 kcal, while fruits and vegetables made the lowest contribution to CBD. Red meat, sugary drinks, and UPF were the main contributors to the environmental impacts of the CBD. The environmental impact/1000 kcal of the CBD was nearly double (CF:3.1 kg(95%IC: 3.0;3.1); WF:2,705 L 95%IC:2,671;2,739)) the cost of the BDG diet (CF:1.4 kg (95%IC:1.4;1.4); WF:1,542 L (95%IC:1,524;1,561)) and EAT-Lancet diet (CF:1.1 kg (95%IC:1.0;1.1); WF:1,448 L (95%IC:1,428;1,469)). A one standard deviation increase in standardized CF corresponded to an increase of BRL$0.48 in the cost of the CBD, similar to standardized WF (BRL$0.56). A similar relationship between the environmental impact and the cost of the BDG (CF: BRL$0.20; WF: BRL$0.33) and EAT-Lancet (CF: BRL$0.04; WF: BRL$0.18) was found, but with a less pronounced effect.

CONCLUSIONS

The BDG diet was cost-effective, while the EAT-Lancet diet was slightly pricier than the CBD. The CBD presented almost double the CF and WF compared to the BDG and EAT-Lancet diets. The lower cost in each diet was associated with lower environmental impact, particularly for the BDG and EAT-Lancet diets. Multisectoral public policies must be applied to guide individuals and societies towards healthier and more sustainable eating patterns.

Cost and Affordability of Habitual and Recommended Diets in Welfare-Dependent Households in Australia

It is crucial to ensure healthy diets are affordable in low socioeconomic groups, such as welfare-dependent households, who experience higher rates of diet-related disease than others. This study assessed the cost of habitual (unhealthy) and recommended (healthy) diets in six welfare-dependent and six other, comparable Australian households, using either popular branded products or the cheapest available alternatives. It also assessed diet affordability in welfare-dependent households, before and after modest increases in government welfare payments introduced in early September 2023. Results confirmed that recommended diets were less expensive than habitual diets in all households unless the cheapest available products were included. This strategy reduced habitual diet costs by 35-37% and recommended diet costs by 30-32%. The lower cost differential could aid perceptions that healthy foods are more expensive than unhealthy foods. In April 2023, 23-37% of the income of welfare-dependent households with children was required to purchase recommended diets; this reduced only to 20-35% in September 2023. Hence, the increases in welfare payments were insufficient to meaningfully improve the affordability of healthy diets in the most vulnerable Australians. In the current cost-of-living crisis, there is an urgent need for more welfare support to help purchase healthy diets. Monitoring of diet cost and affordability is also required.

Examining the New Zealand school food environment: what needs to change?

Habitual dietary intakes and nutrition behaviours developed during childhood and adolescence pave the way for similar behaviours to manifest in adulthood. Childhood obesity rates have now reached a point where one in six children globally are classified as overweight or obese. Schools have the unique ability to reach almost all children during key developmental stages, making them an ideal setting for influencing children's nutrition behaviours. Evidence suggests the school food environment is not always conducive to healthy food choices and may be obesogenic. The aim of this narrative review is to explore factors that influence the healthy food and drink environment in and around schools in New Zealand. The review focused on evidence from New Zealand and Australia given the close resemblance in education systems and school food guidance. Using the Analysis Grid for Environments Linked to Obesity (ANGELO) framework, the school food environment was categorised into the following domains: economic, political, physical and socio-cultural factors. Findings suggest that food policies are not utilised within schools, and guidelines to improve the school food environment are not well implemented. Canteen profit models, lack of staff support and resources, and higher availability of low-cost unhealthy foods are among barriers that hinder implementation. This review highlights recommendations from existing evidence, including canteen pricing strategies, restriction of unhealthy foods and using peer modelling in a time-scarce curriculum to improve the school food environment. Key areas for improvement, opportunities to enhance policy implementation and untapped avenues to improve the food and nutrition behaviours of children are highlighted.

Parental work hours and household income as determinants of unhealthy food and beverage intake in young Australian children

OBJECTIVE

This study examined parental work hours and household income as determinants of discretionary (energy dense, nutrient poor) food and beverage intake in young children, including differences by eating occasion.

DESIGN

Secondary analysis of cross-sectional data. Three hierarchical regression models were conducted with percent energy from discretionary food and beverages across the day, at main meals, and at snack times being the outcomes. Dietary intake was assessed by 1x24-hour recall and 1-2x24-hour food record(s). Both maternal/paternal work hours were included, and total household income. Covariates included household, parent and child factors.

SETTING

Data from the NOURISH/SAIDI studies were collected between 2008-13.

PARTICIPANTS

Participants included 526 mother-child dyads (median(IQR) child age 1.99(1.96,2.03) years). Forty-one percent of mothers did not work while 57% of fathers worked 35-40 hours/week. Most (85%) households had an income of ≥$50k AUD/year.

RESULTS

Household income was consistently inversely associated with discretionary energy intake (β= -0.12 to -0.15). Maternal part-time employment (21-35 hours/week) predicted child consumption of discretionary energy at main meals (β=0.10, p=0.04). Paternal unemployment predicted a lower proportion of discretionary energy at snacks (β= -0.09, p=0.047).

CONCLUSIONS

This work suggests that household income should be addressed as a key opportunity-related barrier to healthy food provision in families of young children. Strategies to reduce the time burden of healthy main meal provision may be required in families where mothers juggle longer part-time working hours with caregiving and domestic duties. The need to consider the role of fathers and other parents/caregivers in shaping children's intake was also highlighted.

Assessing the Cost of Healthy and Unhealthy Diets: A Systematic Review of Methods

PURPOSE OF REVIEW

Poor diets are a leading risk factor for chronic disease globally. Research suggests healthy foods are often harder to access, more expensive, and of a lower quality in rural/remote or low-income/high minority areas. Food pricing studies are frequently undertaken to explore food affordability. We aimed to capture and summarise food environment costing methodologies used in both urban and rural settings.

RECENT FINDINGS

Our systematic review of high-income countries between 2006 and 2021 found 100 relevant food pricing studies. Most were conducted in the USA (n = 47) and Australia (n = 24), predominantly in urban areas (n = 74) and cross-sectional in design (n = 76). All described a data collection methodology, with just over half (n = 57) using a named instrument. The main purpose for studies was to monitor food pricing, predominantly using the 'food basket', followed by the Nutrition Environment Measures Survey for Stores (NEMS-S). Comparatively, the Healthy Diets Australian Standardised Affordability and Price (ASAP) instrument supplied data on relative affordability to household incomes. Future research would benefit from a universal instrument reflecting geographic and socio-cultural context and collecting longitudinal data to inform and evaluate initiatives targeting food affordability, availability, and accessibility.

Benchmarking as a Public Health Strategy for Creating Healthy Food Environments: An Evaluation of the INFORMAS Initiative (2012-2020)

Diet-related noncommunicable diseases (NCDs) and obesity are the leading contributors to poor health worldwide. Efforts to improve population diets need to focus on creating healthy food environments. INFORMAS, established in 2012, is an international network that monitors and benchmarks food environments and related policies. By 2020, INFORMAS was active in 58 countries; national government policies were the most frequent aspect benchmarked. INFORMAS has resulted in the development and widespread application of standardized methods for assessing the characteristics of food environments. The activities of INFORMAS have contributed substantially to capacity building, advocacy, stakeholder engagement, and policy evaluation in relation to creating healthy food environments. Future efforts to benchmark food environments need to incorporate measurements related to environmental sustainability. For sustained impact, INFORMAS activities will need to be embedded within other existing monitoring initiatives. The most value will come from repeated assessments that help drive increased accountability for improving food environments.

Adoption of healthy and sustainable diets in Mexico does not imply higher expenditure on food

The relative cost of healthy and sustainable diets is key for their adoption in different countries. Using a newly developed modelling tool that generates different diet baskets, we compared the costs of diets following the EAT-Lancet healthy reference diet, the Mexican dietary guidelines and locals' current food intake. On average, the cost of the EAT-Lancet healthy reference diet baskets was 21% lower than that of the Mexican dietary guidelines baskets, and 40% lower than that of the current intake baskets (29% lower if the comparison was isocaloric). Findings were similar over time (2011-2018) and by geographic region. The higher cost associated with the larger amount of fruits, vegetables, legumes and nuts in healthy and sustainable diets was surpassed by the savings associated with their lower amount of animal protein sources, sugar-sweetened beverages and discretionary foods. We conclude that transitioning to better diets in Mexico is possible without a higher expenditure on food.

Nutrient Dense, Low-Cost Foods Can Improve the Affordability and Quality of the New Zealand Diet-A Substitution Modeling Study

The high prevalence of non-communicable disease in New Zealand (NZ) is driven in part by unhealthy diet selections, with food costs contributing to an increased risk for vulnerable population groups. This study aimed to: (i) identify the nutrient density-to-cost ratio of NZ foods; (ii) model the impact of substituting foods with a lower nutrient density-to-cost ratio with those with a higher nutrient density-to-cost ratio on diet quality and affordability in representative NZ population samples for low and medium socioeconomic status (SES) households by ethnicity; and (iii) evaluate food processing level. Foods were categorized, coded for processing level and discretionary status, analyzed for nutrient density and cost, and ranked by nutrient density-to-cost ratio. The top quartile of nutrient dense, low-cost foods were 56% unprocessed (vegetables, fruit, porridge, pasta, rice, nuts/seeds), 31% ultra-processed (vegetable dishes, fortified bread, breakfast cereals unfortified <15 g sugars/100 g and fortified 15-30 g sugars/100 g), 6% processed (fruit juice), and 6% culinary processed (oils). Using substitution modeling, diet quality improved by 59% and 71% for adults and children, respectively, and affordability increased by 20-24%, depending on ethnicity and SES. The NZ diet can be made healthier and more affordable when nutritious, low-cost foods are selected. Processing levels in the healthier, modeled diet suggest that some non-discretionary ultra-processed foods may provide a valuable source of low-cost nutrition for food insecure populations.

Cost and greenhouse gas emissions of current, healthy, flexitarian and vegan diets in Aotearoa (New Zealand)

Objective

To compare the costs and climate impact (greenhouse gas emissions) associated with current and healthy diets and two healthy and environmentally friendly dietary patterns: flexitarian and vegan.

Design

Modelling study

Setting

Aotearoa (New Zealand).

Main outcome measures

The distribution of the cost and climate impact (kgCO₂e/kg of food per fortnight) of 2 weekly current, healthy, vegan and flexitarian household diets was modelled using a list of commonly consumed foods, a set of quantity/serves constraints for each, and constraints for food group and nutrient intakes based on dietary guidelines (Eating and Activity Guidelines for healthy diets and EAT-Lancet reference diet for vegan and flexitarian diets) or nutrition survey data (current diets).

Results

The iterative creation of 210–237 household dietary intakes for each dietary scenario was achieved using computer software adapted for the purpose (DIETCOST). There were stepwise differences between diet scenarios (p<0.001) with the current diet having the lowest mean cost in New Zealand Dollars (NZ$584 (95% CI NZ$580 to NZ$588)) per fortnight for a family of four) but highest mean climate impact (597 kgCO₂e (95% CI 590 to 604 kgCO₂e)), followed by the healthy diet (NZ$637 (95% CI NZ$632 to NZ$642), 452 kgCO₂e (95% CI 446 to 458 kgCO₂e)), the flexitarian diet (NZ$728 (95% CI NZ$723 to NZ$734), 263 kgCO₂e (95% CI 261 to 265 kgCO₂e)) and the vegan diet, which had the highest mean cost and lowest mean climate impact (NZ$789, (95% CI NZ$784 to NZ$794), 203 kgCO₂e (95% CI 201 to 204 kgCO₂e)). There was a negative relationship between cost and climate impact across diets and a positive relationship within diets.

Conclusions

Moving from current diets towards sustainable healthy diets (SHDs) will reduce climate impact but generally at a higher cost to households. The results reflect trade-offs, with the larger constraints placed on diets, the greater cost and factors such as nutritional adequacy, variety, cost and low-emissions foods being considered. Further monitoring and policies are needed to support population transitions that are country specific from current diets to SHD.

Diet and Economic Modelling to Improve the Quality and Affordability of the Australian Diet for Low and Medium Socioeconomic Households

Food costs are a barrier to healthier diet selections, particularly for low socioeconomic households who regularly choose processed foods containing refined grains, added sugars, and added fats. In this study, the objectives were to: (i) identify the nutrient density-to-cost ratio of Australian foods; (ii) model the impact of substituting foods with lower nutrient density-to-cost ratio with those with the highest nutrient density-to-cost ratio for diet quality and affordability in low and medium socioeconomic households; and (iii) evaluate food processing levels. Foods were categorized, coded for processing level, analysed for nutrient density and cost, and ranked by nutrient density-to-cost ratio. The top quartile of nutrient dense, low-cost foods included 54% unprocessed (vegetables and reduced fat dairy), 33% ultra-processed (fortified wholegrain bread and breakfast cereals <20 g sugars/100 g), and 13% processed (fruit juice and canned legumes). Using substitution modelling, diet quality improved by 52% for adults and 71% for children across all households, while diet affordability improved by 25% and 27% for low and medium socioeconomic households, respectively. The results indicate that the quality and affordability of the Australian diet can be improved when nutritious, low-cost foods are selected. Processing levels in the healthier modelled diets suggest that some ultra-processed foods may provide a beneficial source of nutrition when consumed within national food group recommendations.

The potential impact of an implemented income redistribution package on obesity prevalence in New Zealand

AIM

This study quantified associations between (absolute and relative) individual income and obesity prevalence. These associations were then used to model the potential effect of a New Zealand (NZ) Government's income redistributive policy (the Families Package) on adult obesity prevalence.

METHODS

Logistic regressions were used to investigate associations between absolute individual income and adult obesity prevalence in NZ. Linear regressions were used to assess associations between relative income (income inequality measured by Gini) and obesity prevalence (from the NCD-RisC) for OECD countries. Potential impact fractions were calculated to determine how income redistribution might affect obesity prevalence.

FINDINGS

Absolute individual disposable income was significantly associated with obesity in NZ females (but not males) in a shallow, inverted J-shaped fashion. Income inequality was significantly positively associated with obesity prevalence in NZ females but not in males. The Families Package had a modest effect on income distribution and reduced Gini in NZ by 1.43%. Female obesity prevalence in NZ was modelled to decrease by 0.12 percentage points and 0.98 percentage points due to changes to absolute income and income inequality, respectively.

CONCLUSIONS

Despite being the most substantial income tax package in New Zealand since the 1990s, this policy had a modest effect on income redistribution, and its expected impact on reducing obesity in females was also modest, with no effect in males. The J-shaped curve indicates that income redistribution could even increase obesity prevalence among low-income women.

The Retail Food Sector and Indigenous Peoples in High-Income Countries: A Systematic Scoping Review

Indigenous Peoples in high-income countries experience higher burdens of food insecurity, obesity, and diet-related health conditions compared to national averages. The objective of this systematic scoping review is to synthesize information from the published literature on the methods/approaches, findings, and scope for research and interventions on the retail food sector servicing Indigenous Peoples in high-income countries. A structured literature search in two major international databases yielded 139 relevant peer-reviewed articles from nine countries. Most research was conducted in Oceania and North America, and in rural and remote regions. Several convergent issues were identified across global regions including limited grocery store availability/access, heightened exposure to unhealthy food environments, inadequate market food supplies (i.e., high prices, limited availability, and poor quality), and common underlying structural factors including socio-economic inequality and colonialism. A list of actions that can modify the nature and structure of retailing systems to enhance the availability, accessibility, and quality of healthful foods is identified. While continuing to (re)align research with community priorities, international collaboration may foster enhanced opportunities to strengthen the evidence base for policy and practice and contribute to the amelioration of diet quality and health at the population level.

Food cost and adherence to guidelines for healthy diets: evidence from Belgium

BACKGROUND/OBJECTIVES

Evidence on whether healthy diets are more expensive than less healthy diets is mixed. The relative cost of meeting healthy diet guidelines in Belgium was estimated.

SUBJECTS/METHODS

Data from the nationally representative food consumption survey (FCS) 2014-2015 (n = 3146; 3-64 years) were used. Dietary data were collected through two non-consecutive 24-h recalls (records for children). Average prices for >2000 foods were retrieved from the 2014 GfK ConsumerScan panel and linked with foods consumed in the FCS. Daily costs of meeting nutritional guidelines were estimated across age and household education level groups.

RESULTS

Processed meat contributed most (9.8%-14.4% dependent on age group) to the daily cost of diets. Soft drinks contributed to the daily cost more while fruits and vegetables contributed less for lower versus higher educated households. Compared to individuals not meeting any nutrient recommendations (sodium, saturated fat, free sugar, fibre), the average cost/2000 kcal was significantly higher for individuals meeting one (0.36 ± 0.11€, p = 0.001), two (0.87 ± 0.14€, p < 0.001) or three or more (1.44 ± 0.24€, p < 0.001) recommendations. Similarly, compared to individuals not meeting any of the food-based recommendations (fruit, vegetables, wholegrain, nuts and seeds, red meat, processed meat), the average cost/2000 kcal was significantly higher for individuals meeting three or more (1.04 ± 0.27€; p < 0.001) recommendations. For adults, diets meeting guidelines for vegetables were 20% and for fruits 10% more expensive than diets not meeting those guidelines.

CONCLUSIONS

The cost of diets of Belgian people meeting healthy diet guidelines is greater than of those not meeting guidelines. Policies that make healthy diets more affordable are recommended.

Streamlined data-gathering techniques to estimate the price and affordability of healthy and unhealthy diets under different pricing scenarios

OBJECTIVE

To determine the reliability of streamlined data-gathering techniques for examining the price and affordability of a healthy (recommended) and unhealthy (current) diet. We additionally estimated the price and affordability of diets across socio-economic areas and quantified the influence of different pricing scenarios.

DESIGN

Following the Healthy Diets Australian Standardised Affordability and Pricing (ASAP) protocol, we compared a cross-sectional sample of food and beverage pricing data collected using online data and phone calls (lower-resource streamlined techniques) with data collected in-store from the same retailers.

SETTING

Food and beverage prices were collected from major supermarkets, fast food and alcohol retailers in eight conveniently sampled areas in Victoria, Australia (n 72 stores), stratified by area-level deprivation and remoteness.

PARTICIPANTS

This study did not involve human participants.

RESULTS

The biweekly price of a healthy diet was on average 21 % cheaper ($596) than an unhealthy diet ($721) for a four-person family using the streamlined techniques, which was comparable with estimates using in-store data (healthy: $594, unhealthy: $731). The diet price differential did not vary considerably across geographical areas (range: 18-23 %). Both diets were estimated to be unaffordable for families living on indicative low disposable household incomes and below the poverty line. The inclusion of generic brands notably reduced the prices of healthy and unhealthy diets (≥20 %), rendering both affordable against indicative low disposable household incomes. Inclusion of discounted prices marginally reduced diet prices (3 %).

CONCLUSIONS

Streamlined data-gathering techniques are a reliable method for regular, flexible and widespread monitoring of the price and affordability of population diets in areas where supermarkets have an online presence.

The first INFORMAS national food environments and policies survey in New Zealand: A blueprint country profile for measuring progress on creating healthy food environments

The International Network for Food and Obesity/NCDs Research, Monitoring and Action Support aims to benchmark national food environments. This study proposes a blueprint country profile to measure progress on creating healthy food environments, based on the results of the first, comprehensive survey in New Zealand (NZ). We assessed the implementation of national food environment policies and food industry commitments to improve population nutrition and the strength and comprehensiveness of public sector settings' nutrition policies. The healthiness of the packaged food supply, including health-related labelling, was evaluated. Food environments were measured in 833 schools, 204 supermarkets, 1500 takeaway outlets, 28 hospitals, 70 sport centres, and around all NZ schools. Food swamps, defined as areas with high relative density of unhealthy food outlets, were identified, and food marketing to children on television, websites, social media and packages, in magazines, and in and around schools was measured. The cost differential between healthy and current household diets was calculated for different population groups. NZ's food environment profile is largely unhealthy, and there are inequalities in access to healthy food environments. It is anticipated that the proposed country profile can help other countries tackle unhealthy food environments through increasing accountability of governments and the industry.