The novel PHD basket for Australians was found to be both less expensive and more affordable than the TAD basket nationally, in all metropolitan areas, and across all SEIFA-IRSAD quintiles. This research suggests that healthy and sustainable diets such as the PHD are highly feasible in the Australian context, in terms of the basket contents being potentially affordable, available and purchased in large-scale retail outlets in metropolitan settings.
Results indicated that an average of $AUD189.20 (≈$USD120) per week was required to consume a diet consistent with the PHD, compared to an average of $AUD224.66 (≈$USD145) per week for the TAD. If adopted over a one year period, the PHD would result in savings of $AUD1843.92 (≈$USD1200) per year to the household food budget for a family of two adults and two children. This study also found SEIFA-IRSAD quintile 1 households are required to dedicate an average of 17% of their weekly income to a healthy and sustainable diet, compared to 21% of their weekly income required for a typical diet, indicating that the PHD would be more affordable for metropolitan-dwelling Australians than what was typically consumed currently regardless of socio-economic (dis)advantage.
The national mean food basket affordability results from this study were consistent with ABS data showing Australians spend approximately 17% of their disposable income on food and non-alcoholic beverages82,83 – in other words, the results of this study’s surveys fell into the expected range. All SEIFA-IRSAD quintiles in all metropolitan areas were within the acceptable range of food affordability (not more than 30% of disposable income),72,84-87 however the Darwin SEIFA-IRSAD quintile 1 survey area was nearing the domain of potential food stress for both the PHD and TAD baskets,51,72,85 with the baskets costing 24% and 28% of disposable income respectively.
Results of the present study are in contrast to a similar Australian study by Barosh et al. which found that a healthy and sustainable diet is more expensive than the TAD.51 However, the disparity in results could be explained by differing methods – the surveys for the present study were conducted only in major supermarkets (Coles and Woolworths together account for around 80% of the total grocery spend in Australia),69 whereas Barosh et al. surveyed food price data from a variety of retail outlets including small corner stores, which the authors indicated are more expensive than supermarkets.51 In addition, the Barosh et al. healthy and sustainable basket was composed of different items to the PHD basket, and included more meat which would inevitably increase the cost of the basket, especially from smaller retail outlets.51 Further, the Barosh et al. food basket surveys were conducted in 2011, and food costs may have changed since that time. Two studies from United Kingdom also showed that a healthy and sustainable diet cost the same or less than the typical current United Kingdom diet, consistent with the present study’s findings even though different methods were used (one study collected food costs of mid-range items from supermarkets,66 and one study collected food costs from all retail sources from consumer’s actual purchases).65 Additionally, Hirvonen et al. also concluded that the PHD was affordable in high-income countries such as Australia, also consistent with the present study’s findings.67
A 2013 global review on food prices and affordability showed that for some consumers price is more of a purchasing determinant than taste, and that consumers generally purchase more food when prices fall and less food when prices rise.54 Although the affordability of the PHD for metropolitan-dwelling Australians shopping at major supermarkets has now been demonstrated, it remains unclear if, and to what extent, the cost of fluctuating food prices could affect consumer adoption of this diet, particularly lower-income consumers who are more price sensitive than higher-income consumers.56 This could become more of an issue in the future as it is predicted that food prices will rise due to issues associated with climate change, which will affect affordability and therefore accessibility of food for many people.2,9
The results of the present study suggest that a diet modelled on the PHD reference diet is feasible in regards to the weekly cost, amounts and availability of food for a range of Australians. This PHD basket was designed to accommodate Australian food preferences, and considered item availability in Australia75 (the only item alteration was coconut oil replacing palm oil, as palm oil is neither readily accessible nor popular in Australian cuisine). Kangaroo meat was considered for inclusion due to its relatively low environmental footprint,9,75,88 however as this meat is not farmed but hunted on a quota system which varies between states and is dependent on the wild kangaroo population size, the supply of kangaroo meat may not be large enough or consistent enough to meet demand if the PHD is widely adopted.89 Compared to the TAD, the total amount of meat was reduced, but most important was the reduction of ruminant meat – from 1168g (TAD) down to 185g (PHD). As ruminants are a large contributor to greenhouse gasses due to their methane output, this contributes greatly to the lower environmental footprint of the PHD.3,14
As the present results demonstrate, the PHD was less expensive and more affordable than the current TAD across socioeconomic groups. That does not mean that the PHD will be widely adopted, however this study was addressing affordability not consumer acceptability. As the PHD contains more fresh produce and no pre-prepared foods, it requires more preparation time and manual cooking than the TAD. This could be an issue for those who do not like or know how to cook, or those who are time-poor (e.g. full-time workers, single parents) and may make acceptance and compliance more difficult. The inclusion of more fresh produce also means that the basket as a whole is more perishable, hence households may need to shop more regularly than for the TAD – this could reduce feasibility of adopting the PHD for time-poor families, those who need to travel long distances to get to food retail outlets, and those who rely on public transport for travel.
The PHD basket could be made even cheaper by further reducing or even eliminating the meat portion, eating seasonally when fresh produce will be at its cheapest, buying dry goods in bulk, utilising supermarket special buys and price mark-downs, and replacing some items (e.g. fresh salmon could be replaced with less expensive tinned salmon).68 Likewise, the meat portion could be increased to the upper allowable limit and still be within the boundaries of the PHD diet, but this would increase the cost, as would purchasing smaller quantities and eating fresh produce out of season.68 Therefore, the results of this study are susceptible to change based on consumer’s individual eating and shopping habits.
While this study has endeavoured to be as accurate as possible, it is not without limitations. The PHD basket contents do not consider medical dietary restrictions such as gluten-free diets for coeliacs, although this is also true for other existing food baskets.51,61,62,65,66,90-94 The TAD basket, while developed from surveys of actual consumption, may not be representative of an individual’s consumption, and was based on the 1995 National Nutrition Survey40 – although the most current TAD basket available was used for this study due to time and resource constraints, future TAD baskets should be informed by the more recent 2011-13 National Nutrition and Physical Activity Survey. In addition, the present survey only used one supermarket chain so may not be representative of the cost of items purchased elsewhere, e.g. corner stores, farmers markets or grown at home. The survey also does not consider that consumers’ food choices may be influenced by sale prices, which could alter both the contents and the cost of the baskets.49-60 The PHD basket cost did not consider varied household sizes, structures or incomes, or eating outside the home such as restaurant meals (which accounts for 34% of Australian total food expenditure),95 although this was also true for the TAD basket therefore the comparison between the two baskets is still appropriate. In regards to taste preferences, the substantial reduction of meat in the PHD may be an obstacle for many consumers, even considering the potential financial savings associated with the PHD diet. Despite these limitations, this study still provides a worthwhile and novel contribution to the literature regarding healthy and sustainable food baskets, and the affordability of these food baskets in Australia.
5.1 Strengths and contributions to literature
To our knowledge, this study is the first time that a food basket has been developed that is modelled on the PHD, contributing to current literature on both development and use of food baskets, and healthy and sustainable diets for different population groups. Additionally, to our knowledge, this study is the first time that a PHD basket has been costed for affordability in Australia, and that food baskets in general have been costed for affordability nationally across various socio-economic groups. This cost and affordability analysis of the PHD basket fills a gap left by the EAT–Lancet Commission, which did not address the diet’s economic viability for consumers in Australia3 (global affordability has been analysed in other studies).67 Further research is needed to ascertain the financial feasibility of the PHD diet in rural and remote areas of Australia where food baskets cost more than in metropolitan areas,72,90,92,96 as well as constructing and costing PHD food baskets for particular dietary habits such as gluten free and vegetarian and perhaps sub-population groups such as varying employment status, family structure and cultural ancestry. This study suggests that price may not be a major hurdle to shift towards sustainable and nutritious diets, and therefore attention on other consumer behaviours and levers for change is required. Further research is needed to ascertain consumer acceptance of the types and quantities of various foods that should be included in a healthy and sustainable diet, in particular the Planetary Health Diet or similar, and to determine the best method to facilitate this dietary change for all Australians.
5.2 Implications
This study has shown that the PHD is a potentially affordable, and therefore financially feasible, diet for metropolitan-dwelling Australians regardless of socio-economic status or location. These results can help to inform public health and food policy aimed at achieving a healthy and sustainable future for all Australians. This can lead to a reduction in overweight/obesity rates and subsequent non-communicable diseases, and increased food security in the face of predicted population increases and environmental uncertainty due to global climate change effects. These results add to the available evidence used to promote food and nutrition literacy for Australians, and consumers may transition their dietary behaviour towards the PHD if not to be healthier and more environmentally friendly, then perhaps for financial benefits. For example, the existing Health Star Rating System97 which currently rates the nutritional profile of food items, could potentially include a comparison of sustainability profiles to help consumers choose food items which fit into the framework of the PHD; or perhaps a new “Planetary Health Diet” or sustainability logo could be developed and used on PHD-compliant food items to encourage consumers to choose wisely. Given the likely increased time and cooking skills required by consumers to adopt the PHD, creating and supporting education campaigns based around food preparation and cooking skills would also be needed.