Eating to live or living to eat? Exploring the link between calorie satiation, Bennett’s law, and the evolution of food preferences

As people become wealthy, the type of food they consume tends to fundamentally change. Bennett’s law states that the budget share of starchy food staples, such as cereals and rice, tends to decline as household income rises, while the budget share of other foods, such as meat and vegetables, tends to rise. We argue that an important factor behind this shift is the extent to which the caloric value of the household’s diet meets their energy needs. When the caloric value of the diet is too low, the demand for calories is unsatiated and household’s will ‘eat to live’ and prefer to consume more calorie-dense staple foods, relative to other foods. If the calorie intake exceeds daily energy needs, satiated consumers will ‘live to eat’ and prefer to dedicate additional income to consuming more non-starchy foods that satisfy other wants, such as taste, novelty, or social status. Using Sri Lankan household data, we employ a finite mixture model (FMM) to analyze how satiated and unsatiated groups of consumers alter their calorie intake as income rises. We find empirical evidence that supports this conjecture and suggests that calorie satiation plays an important role in enabling food preferences to evolve as income rises. Policy implications are also discussed.