The cost of food

Comparisons of the cost of different foods relative to their energy and nutritive value were conducted in the 1800s by the US Department of Agriculture (USDA). The objective of this American Journal of Clinical Nutrition study was to reestablish the relations between food cost, energy, and nutrients by using contemporary nutrient composition and food prices data from the USDA.

For 1387 foods, key variables were as follows: energy density (kcal/g), serving size (g), unit price ($/100 g), serving price ($/serving), and energy cost ($/kcal). A regression model tested associations between nutrients and unit price ($/100 g).

• Grains and fats food groups supplied the lowest-cost dietary energy.

• The energy cost for vegetables was higher than that for any other food group except for fruit.

• The highest prices per serving were for meats, poultry, and fish.

• The lowest prices per serving were for the fats category.

• Although carbohydrates, sugar, and fat were associated with lower price per 100 g, protein, fiber, vitamins, and minerals were associated with higher price per 100 g, after adjustment for energy.
  

• Grains and sugars food groups were cheaper than vegetables and fruit per calorie and were cheaper than fruit per serving.
  

These price differentials may help to explain why low-cost, energy-dense foods that are nutrient poor are associated with lower education and incomes.