The cost of food is a key influence on diet. The majority of diet cost studies match intake data from population-based surveys to a single source of food supply prices. Our aim was to examine the methodological significance of using food supply data to price dietary intakes.

Nationally representative 24-h dietary recall data from the 2015 Canadian Community Health Survey-Nutrition (CCHS-N) was matched to the 2015 Canadian Consumer Price Index (CPI) food price list. Proportions and means of reported intakes covered by the 2015 CPI price list were used to compare reported intakes of food groups and food components of interest and concern overall and by quartile of CPI coverage.

Canada.

In total, 20 487 Canadians ages one and older.

The CPI covered on average 76·3 % of total dietary intake (g) without water. Staple food groups that were more commonly consumed had better CPI price coverage than those less commonly consumed. Yet some food groups (vegetables, additions and sweets) that were also commonly consumed by Canadians were not well covered by price data. Individuals in the poorest CPI coverage quartile reported consuming significantly greater gram weight (g), dietary fibre (g) and energy (kcal) as compared with those with the best coverage.

Differential CPI price coverage exists among food components and commonly consumed food groups; additionally dietary intake differs significantly in the population by CPI coverage. Methodological refinements are needed to better account for error when using prices from food supply data to estimate diet costs.

To assess the association between diet cost and quality by place of residence.

We analysed cross-sectional data of the National Health and Nutrition Survey-2012. Diet cost was estimated by linking dietary data, obtained from a 7-d SFFQ, with municipality food prices, which were derived from a national expenditure survey. Diet quality was assessed using the Healthy Eating Index-2015 (HEI-2015). Association between quintiles of diet cost and HEI-2015 was assessed using linear regression analysis.

Mexico.

2438 adults (18–59 years).

Diet cost was positively associated with diet quality (HEI-2015) in urban but not in rural areas. Compared with quintile (Q1) of cost, the increment in diet quality score was 1·17 (95 % CI –0·06, 4·33) for Q2, 2·14 (95 % CI –0·06, 4·33) for Q3, 4·70 (95 % CI 2·62, 6·79) for Q4 and 6·34 (95 % CI 4·20, 8·49) for Q5 (P-trend < 0·001). Individuals in rural v. urban areas on average have higher quality diets at lower cost with higher intakes of whole grains and beans and lower intakes of Na, added sugars and saturated fats. Living in the South, being indigenous and having low socio-economic status were also associated with higher quality diets.

Diet cost was positively associated with diet quality, but only in urban areas. Further studies are needed to understand the relation between diet cost and quality in rural areas. To improve overall diet quality in Mexico, strategies that aim to reduce the cost of high-quality diets should consider the heterogeneity by place of residence.

People with lactose intolerance have to limit their consumption of lactose-containing dairy products which are a main source of Ca. In particular, for low-income people it is of interest which alternative diet form rich in Ca leads to the lowest additional costs. This study aims to calculate the additional costs of lactose-reduced diets and to show which of different options represent the most cost-effective alternative within a lactose-reduced diet.

Using linear programming, food baskets with different lactose contents were calculated and were compared to a basic model, reflecting a normal diet without a limitation of lactose. By comparing the costs and the composition of the food baskets, recommendations for a lactose-reduced diet were derived.

Germany.

A consumer panel dataset representative for Germany is used for the calculations. Information on prices and nutrients is derived from the 9429 adult households without children, and information on consumed food quantities from the 3046 single households.

The minimum additional food costs depend on the severity of lactose intolerance and range from 0·2 % to 6·1 % per month. It was found that the greatest adjustments due to lactose reduction could be observed within the dairy product group. In this group, with a rising lactose limit, normal milk was increasingly replaced by lactose-free milk.

It was shown that a lactose-reduced diet is generally associated with higher food costs. When suffering from lactose intolerance, switching to lactose-free milk seems to be the most cost-effective way to cover nutrient requirements.

To evaluate the association between diet quality and cost for foods purchased for consumption at home and away from home.

Cross-sectional analysis. Multivariable linear regression models evaluated the association between diet quality and cost for all food, food at home (FAH) and food away from home (FAFH).

Daily food intake data from the National Health and Nutrition Examination Survey (2005–2016). Food prices were derived using data from multiple, publicly available databases. Diet quality was assessed using the Healthy Eating Index-2015 and the Alternative Healthy Eating Index-2010.

30 564 individuals ≥20 years with complete and reliable dietary data.

Mean per capita daily diet cost was $14·19 (95 % CI (13·91, 14·48)), including $6·92 (95 % CI (6·73, 7·10)) for FAH and $7·28 (95 % CI (7·05, 7·50)) for FAFH. Diet quality was higher for FAH compared to FAFH (P < 0·001). Higher diet quality was associated with higher food costs overall, FAH and FAFH (P < 0·001 for all comparisons).

These findings demonstrate that higher diet quality is associated with higher costs for all food, FAH and FAFH. This research provides policymakers, public health professionals and clinicians with information needed to support healthy eating habits. These findings are particularly relevant to contemporary health and economic concerns that have worsened because of the COVID-19 pandemic.

To assess the compatibility between reduction of diet-related greenhouse gas emissions (GHGE) and nutritional adequacy, acceptability and affordability dimensions of diet sustainability.

Dietary intake, nutritional composition, GHGE and prices were combined for 402 foods selected among those most consumed by participants of the Individual National Study on Food Consumption. Linear programming was used to model diets with stepwise GHGE reductions, minimized departure from observed diet and three scenarios of nutritional constraints: none (FREE), on macronutrients (MACRO) and for all nutrient recommendations (ADEQ). Nutritional quality was assessed using the mean adequacy ratio (MAR) and solid energy density (SED).

France.

Adults (n 1899).

In FREE and MACRO scenarios, imposing up to 30 % GHGE reduction did not affect the MAR, SED and food group pattern of the observed diet, but required substitutions within food groups; higher GHGE reductions decreased diet cost, but also nutritional quality, even with constraints on macronutrients. Imposing all nutritional recommendations (ADEQ) increased the fruits and vegetables quantity, reduced SED and slightly increased diet cost without additional modifications induced by the GHGE constraint up to 30 % reduction; higher GHGE reductions decreased diet cost but required non-trivial dietary shifts from the observed diet. Not all the nutritional recommendations could be met for GHGE reductions ≥70 %.

Moderate GHGE reductions (≤30 %) were compatible with nutritional adequacy and affordability without adding major food group shifts to those induced by nutritional recommendations. Higher GHGE reductions either impaired nutritional quality, even when macronutrient recommendations were imposed, or required non-trivial dietary shifts compromising acceptability to reach nutritional adequacy.

Promotion of healthy eating can no longer be postponed as a priority, given the alarming growth rate of chronic degenerative diseases in Western countries. We elaborated a nutrieconomic model to assess and identify the most nutritious and affordable food choices.

Seventy-one food items representing the main food categories were included and their nationally representative prices monitored. Food composition was determined using CRA-NUT (Centro di Ricerca per gli Alimenti e la Nutrizione) and IEO (Istituto Europeo di Oncologia) databases. To define food nutritional quality, the mean adequacy ratio and mean excess ratio were combined. Both prices and nutritional quality were normalised for the edible food content and for the recommended serving sizes for the Italian adult population.

Stores located in different provinces throughout Italy.

Not applicable.

Cereals and legumes presented very similar nutritional qualities and prices per serving. Seasonal fruits and vegetables presented differentiated nutritional qualities and almost equal prices. Products of animal origin showed similar nutritional qualities and varied prices: the best nutrieconomic choices were milk, oily fish and poultry for the dairy products, fish and meat groups, respectively.

Analysing two balanced weekly menus, our nutrieconomic model was able to note a significant decrease in cost of approximately 30 % by varying animal-protein sources without affecting nutritional quality. Healthy eating does not necessarily imply spending large amounts of money but rather being able to make nutritionally optimal choices. The nutrieconomic model is an innovative and practical way to help consumers make correct food choices and nutritionists increase the compliance of their patients.

To examine diet costs in relation to dietary quality and socio-economic position, and to investigate underlying reasons for differences in diet costs.

Dietary intake was assessed by a 4 d food diary and evaluated using the 2005 Healthy Eating Index (HEI). National consumer food prices collected by Statistics Sweden and from two online stores/supermarkets were used to estimate diet costs.

Sweden.

A nationally representative sample of 2160 children aged 4, 8 or 11 years.

Higher scores on the HEI resulted in higher diet costs and, conversely, higher diet costs were linked to increased total HEI scores. Children who consumed the most healthy and/or expensive diets ate a more energy-dilute and varied diet compared with those who ate the least healthy and/or least expensive diets. They also consumed more fish, ready meals and fruit. Regression analysis also linked increased food costs to these food groups. There was a positive, but weak, relationship between HEI score and diet cost, parental education and parental occupation respectively.

Healthy eating is associated with higher diet cost in Swedish children, in part because of price differences between healthy and less-healthy foods. The cheapest and most unhealthy diets were found among those children whose parents were the least educated and had manual, low-skill occupations. Our results pose several challenges for public health policy makers, as well as for nutrition professionals, when forming dietary strategies and providing advice for macro- and microlevels in society.

The aim of the present work was to calculate the current cost of the Mediterranean diet in Greece and to evaluate the role of diet cost in the development of cardiovascular events after a 5-year follow-up.

Cross-sectional. Cost of diet was measured in €/week based on common Greek dietary choices, while baseline dietary habits were assessed through a semi-quantitative FFQ (Greek-EPIC). The Mediterranean Diet Score (MedDietScore) was applied to assess overall adherence to this pattern using scores of eleven food variables and alcohol, according to the principles of the Mediterranean diet.

Five-year follow-up of the ATTICA study, a nutrition and health survey of a representative, free-living sample of the Greek population resident in the province of Attica, where Athens is a major metropolis.

From 2001 to 2002, 1514 men and 1528 women (aged >18 years) without known CVD were enrolled. In 2006, the 5-year follow-up was performed.

The weekly cost of participants’ diets varied from 5·35 to 83·57 €/week in men (mean 25·45 (sd 6·80) €/week) and from 10·89 to 55·49 €/week in women (mean 25·63 (sd 6·30) €/week). Diet cost was correlated marginally to MedDietScore (r = 0·060, P = 0·05) as well as being associated with history of hypercholesterolaemia (mean (sd), yes v. no: 24·90 (5·73) v. 25·82 (6·95) €/week, P = 0·027), physical activity (mean (sd), yes v. no: 26·42 (6·90) v. 24·82 (6·20) €/week, P < 0·001) and current smoking (mean (sd), yes v. no: 24·99 (6·40) v. 25·98 (6·70) €/week, P = 0·017). No significant association was found between diet cost and 5-year incidence of CVD (hazard ratio = 1·021, 95 % CI 0·965, 1·081). However, adherence to the traditional Mediterranean diet was inversely associated with the development of CVD (relative risk per 1-unit increase in MedDietScore = 0·92, 95 % CI 0·89, 0·94) after adjustment for various potential confounders including diet cost.

Quality but not cost of the diet is associated with the development of CVD.

To test the viability of the Mediterranean diet as an affordable low-energy-density model for dietary change.

Foods characteristic of the Mediterranean diet were identified using previously published criteria. For these foods, energy density (kJ/100 g) and nutrient density in relation to both energy ($/MJ) and nutrient cost were examined.

Some nutrient-rich low-energy-density foods associated with the Mediterranean diet were expensive, however, others that also fit within the Mediterranean dietary pattern were not.

The Mediterranean diet provides a socially acceptable framework for the inclusion of grains, pulses, legumes, nuts, vegetables and both fresh and dried fruit into a nutrient-rich everyday diet. The precise balance between good nutrition, affordability and acceptable social norms is an area that deserves further study. The new Mediterranean diet can be a valuable tool in helping to stem the global obesity epidemic.

Assessing how the Italian average food pattern would be affected in terms of consumption structure and expenditure by the adoption of nutritional prescriptions.

A linear programming model with nutritional and food habits constraints was employed to generate a pattern following recommended daily allowances (RDAs) and nutritional guidelines provided for the Italian population.

Food consumption data from ISTAT Household Budget Survey of Italian population.

Italian families investigated by the Family Budget Survey of the National Institute of Statistics.

Compared to actual behaviour, the pattern generated by the model implies an increased consumption of vegetables, pasta, rice and fresh fish, and a decreased consumption of meats, bread, sugars and cakes, and especially fats and oils. At given prices, total expenditure is lower than actual expenditure.

Differences between actual behaviour and the generated pattern are consistent with long-term trends in food consumption. The adoption of RDAs is unlikely to result in an increased food expenditure.

High consumption of energy-dense foods has been linked to high energy intakes and excess weight gain. This study tested the hypothesis that high energy density of the total diet is associated with lower diet costs.

Dietary intakes of 837 French adults, aged 18–76 years, were assessed using a dietary history method. Dietary energy density (MJ kg−1) was calculated by dividing total energy by the edible weight of foods consumed. Daily diet cost (€day−1) was estimated using mean national food prices for 57 food items. The relationship between dietary energy density and diet cost at each level of energy intake was examined in a regression model, adjusted for gender and age.

The more energy-dense refined grains, sweets and fats provided energy at a lower cost than did lean meats, vegetables and fruit. Within each quintile of energy intake, diets of lower energy density (MJ kg−1) were associated with higher diet costs (€day−1).

In this observational study, energy-dense diets cost less whereas energy-dilute diets cost more, adjusting for energy intakes. The finding that energy-dilute diets are associated with higher diet costs has implications for dietary guidelines and current strategies for dietary change.