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

The Relationship between Diet Costs and Dietary Adequacy: A Scoping Review of Measures and Methods with a Focus on Cost Estimation using Food Supply Data

BACKGROUND

"Diet cost" refers to a methodological approach developed by Drewnowski et al. to estimate individual daily diet costs, where cost vectors are derived by matching prices from food supply data to the food sources of reported intakes from dietary assessment tools. The dietary assessment method and food price collection approach have been found to vary diet cost estimates. There is a need to better understand how food supply prices might be better standardized and attached to price individuals' diets.

OBJECTIVES

To conduct a scoping review to examine Drewnowski's diet cost method, with a focus on a detailed description and charting of cost estimation measures and methods used to price individuals' consumed diets.

METHODS

Five databases were searched from the inception of each database to March 2023. Included articles comprised analyses of individual-level dietary assessment data matched to food prices to assign estimates of individual daily diet costs.

RESULTS

A total of 55 articles were included, published between 1999 and 2022 from 17 countries. In all studies, cost estimates were intended to be representative of price exposures among individual respondents' dietary assessment data. All studies derived cost estimates from separately collected food prices. A total of 34 (62%) of included articles collected food prices from retail (supermarket) audits. A minority of studies (19, 35%) reported the number of food prices used to cost diets, and those varied widely, ranging from 57 to nearly 4600 distinct foods priced per study.

CONCLUSIONS

In the absence of a standardized approach to study the relationship between diet costs and dietary adequacy, this scoping review has described methodological concepts and parameters used to price individuals' consumed diets. Our review shows that despite common arithmetic to calculate cost vectors, there is substantial variation in the methods used to select and attach prices from the food supply to self-reported dietary intake assessments.

Cost-effectiveness of protein-rich meals and snacks for increasing protein intake in older adults

OBJECTIVES

To investigate the cost-effectiveness of protein-rich meals and snacks for increasing protein intake in home-dwelling older adults.

DESIGN

Cost effectiveness analysis from a randomized controlled trial, the Power Meals study.

SETTING

Participants were randomized into one of three groups for eight weeks: a protein-rich meal, snack and bread (Protein), a regular meal (Normal) and a control group without meal service (Control).

PARTICIPANTS

Home-dwelling home care clients, caregivers and care recipients aged ≥65 years (n = 65).

MEASUREMENTS

Protein intake was assessed by a three-day food diary at the end of the study. Cost for the daily diet was estimated by using Finnish grocery store databases and the prices of the food service. The cost-effectiveness was assessed by an incremental cost-effectiveness ratio (ICER).

RESULTS

Costs for the daily diet in the Protein (8.35 €/d) and the Normal (7.94 €/d) groups were significantly higher than in the control group (5.65 €/d) (p < 0.001). Incremental cost-effectiveness analysis showed that increasing protein intake was cost-effective in the Protein group as incremental cost-effectiveness ratio was 8.11 in the Protein, 8.72 in the Normal and 6.45 in the Control group.

CONCLUSIONS

Including protein rich meals and snacks in a diet increases protein intake in home-dwelling older adults cost-effectively.

The Price of Foods, Beverages, and Diets in Australia: An Updated Systematic Review

CONTEXT

The price and affordability of food are priorities for public health and health equity; however, Australia lacks a consistent method to evaluate healthy versus unhealthy diets, creating a gap in routine food price reporting.

OBJECTIVE

This review aimed to identify and summarize recent methods used to assess and monitor the price and/or affordability of food and beverages in Australia using a health lens.

DATA SOURCES

Four academic databases (MEDLINE Complete, Global Health, CINAHL Complete, and Business Source Complete) were searched in English from 2016 to 2022. Relevant gray literature was searched through Google Scholar and government websites.

DATA EXTRACTION

Five reviewers screened titles and abstracts, and full-text screening was conducted by 1 reviewer, with eligibility confirmed by a second reviewer. The quality of studies was assessed using the Joanna Briggs Institute "Checklist for Analytical Cross-Sectional Studies."

DATA ANALYSIS

Twenty-five eligible studies were identified. Eleven studies used a version of the Healthy Diets Australian Standardized Affordability and Pricing protocol to collect prices for a "healthy" diet modelled on dietary guidelines and an "unhealthy" diet based on a habitual Australian diet. These studies consistently found unhealthy diets to be more expensive than healthy diets. Other identified methods included assessing the price of household diets across healthy baskets (n = 6), store types (n = 5), a planetary health diet (n = 1), packaged foods according to their Health Star Rating (n = 1), a fruit and vegetable basket (n = 1), school canteen foods against a traffic light system (n = 1), and weekly healthy meal plans (n = 1). Healthy diets tended to be less costly than less healthy diets, but both diets were often unaffordable in regional areas, for people on low incomes, and for First Nations peoples.

CONCLUSION

Consistent country-wide application of methods for monitoring the price and affordability of foods and diets in Australia is needed-including tailored approaches for priority groups.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO registration no. CRD42022333531.

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.

Food insecurity and academic performance in Spanish adolescents: Results from the EHDLA study

Introduction

Food insecurity is a growing global issue that affects both developed and developing nations, and mounting evidence suggests that decreased consumption of healthy foods has been linked to lower academic performance in adolescents. The present study aimed to examine the relationship between food insecurity and academic performance in a sample of Spanish adolescents aged 12-17 years from the Valle de Ricote (Region of Murcia, Spain).

Methods

The present study analyzed data from the Eating Healthy and Daily Life Activities study, which included a sample of 777 adolescents (55.3 % girls). The Spanish Child Food Security Survey Module was used to assess food insecurity, and academic performance was evaluated using school records provided by the schools. Linear regression models (fitted by robust methods) were used to compare the relationships between food insecurity status and academic performance-related indicators.

Results

Adolescents with the highest levels of food insecurity reported the lowest academic performance in language (mean [M] = 4.7; 95 % confidence interval [CI] 3.6 to 5.7), math (M = 4.6; 95 % CI 3.5 to 5.8), foreign language (M = 4.8; 95 % CI 3.8 to 5.8), and grade point average (M = 5.7; 95 % CI 4.9 to 6.5). Conversely, adolescents with the lowest levels of food insecurity reported the highest academic performance in language (M = 6.2; 95 % CI 6.0 to 6.5), math (M = 5.9; 95 % CI 5.5 to 6.2), foreign language (M = 6.2; 95 % CI 5.9 to 6.4), and grade point average (M = 6.7; 95 % CI 6.5 to 6.9) compared to those with higher food security.

Conclusions

Living in a more food-insecure household could explain the lower academic performance of adolescents. Food insecurity should always be on the agenda of public policies. The availability of quality basic food essentials must be ensured in permanently satisfactory quantities without compromising access to other fundamental needs.

Barriers to Adherence to Healthy Diet and Recommended Physical Activity Perceived by the Polish Population

BACKGROUND

According to the World Health Organization, an unhealthy diet and lack of physical activity constitute the primary global health risks. The purpose of this study was to as-certain the barriers to a healthy diet (HD) and physical activity (PA) as perceived by the Polish population in order to implement public health interventions.

METHODS

A quantitative survey was conducted using the computer-assisted telephone interview technique on a randomly selected representative sample of 2000 Polish citizens aged 18-88 years. The research tool was a questionnaire consisting of two parts: sociodemographic characteristics and examining barriers to an HD (Cronbach's alpha = 0.899) and regular PA (Cronbach's alpha = 0.923).

RESULTS

Women constituted more than half of the sample (53.4%), and most of the respondents lived in urban areas (60.5%), considered their financial situation as average (56.9%), and their health as satisfactory (42.3%). Barriers to an HD include the cost of healthy food (43%), lack of motivation (26.7%), and lack of time (25.4%). Barriers to taking up PA include competing priorities (29%), a lack of motivation to exercise (27.3%), feeling of constant fatigue, and lack of energy (24.4%). Limiting factors in the adoption of both an HD and PA are gender (women > men; HD p < 0.01; PA p < 0.001), financial situation (unsatisfactory; HD and PA p < 0.001), health condition (unsatisfactory; HD and PA p < 0.001), type of work (blue-collar workers; HD p < 0.001; PA p < 0.05), and employment status (people running household; HD and PA p < 0.001).

CONCLUSIONS

The results of this study provide important information about barriers to adopting healthy lifestyle principles. The practical implications of our work can be used by policymakers responsible for intervention strategies and programmes to increase the number of people adhering to recommendations for an HD and PA by removing barriers.