A recent paper published in Nature Food asked what foods would be in the cheapest diet that satisfies nutritional requirements. Combining the prices and food composition data for common food items in the US, the authors determined the cheapest way to feed one person a nutritionally adequate daily diet.
The cost of the diet was calculated as US$1.98 per day (NZ$3.02). It consisted of 15 foods, all of which could be found in the average US home kitchen. The top five contributors were milk, legumes, rice, potatoes and corn tortillas.
The authors also analysed what level of price increase to animal-sourced foods was necessary before the cheapest diet became entirely plant-based. Between 200-1,150% increases in the cost of animal-sourced foods was required, and the plant only diet would cost US$3.61 per day (NZ$5.51). The plant only diet overlapped with the original diet for many foods, but also included soy beverages, green peas and peanut butter.
The authors highlighted that the bioavailability of consumed nutrients was not considered in this study. Inclusion of bioavailability would likely increase the cost of both diets but would have a greater impact on the plant-based diet, due to the lower bioavailability of many nutrients in plant foods. The daily diets proposed by the authors are not recommended diets – a limit of 15 different foods is not feasible – but the work does show that animal-sourced foods can be a cost-effective way to get adequate nutrition.
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