Figure 5.

Potential biological (a,b) and socioeconomic (c,d) influences on processed food consumption. (a) Discretionary foods cluster in a low protein region of three-dimensional macronutrient space, hence are susceptible to over-consumption via protein leverage (from [13]). (b) Response surface generated from hedonic ratings of milk-based mixtures varying in fat, carbohydrate and protein. Results show a close correspondence between the composition of discretionary foods (a) and peak palatability. Recalculated and plotted in three macronutrient dimensions from an experiment designed to assess the effects of variation in fat and sugar ratios [99]. (c) Protein is expensive—the dollar cost of foods increases with increasing protein content and is lowest for diets low in protein and high in carbohydrates (blue region) (replotted from [100]). (d) The correlation between family incomes and dietary macronutrient compositions shows lower incomes are associated with diets lower in protein (as expected from (c)) and higher carbohydrate proportions, possibly explaining associations between socioeconomic status and obesity incidence. Data from the Australian National Nutrition and Physical Activity Survey.