The Stigler Diet: A Mathematical Floor for Human Subsistence

Researchers at Tufts University solved a high-stakes puzzle: what is the absolute minimum price of staying alive and healthy?

By processing 60 food items through linear programming, the team discovered that a 30-year-old woman in an urban setting could satisfy her biological requirements for just $2.88 per day**. For a representative male, that floor rises to **$3.17 per day.

This finding is a critical pulse-check for health equity and poverty measurement.

• It moves the goalposts from "energy-only" survival to "nutrient adequacy."
• A diet of just starchy staples (surviving) costs a mere $0.83 per day globally.
• The true "nutrient adequacy floor" averages $2.32 worldwide—a price point many of the world’s most vulnerable still cannot reach.

To find these prices, the team treated the human body like a high-precision machine.

• They mapped 37 distinct nutrient constraints (21 lower-bound, 16 upper-bound), including strict limits on sodium.
• In a simplified "Three Sisters" model (corn, beans, squash), a diet could hit Iron and Vitamin A targets for $2.48 per day.
• This required consuming exactly 4.82 servings of corn and 1.14 servings of beans, demonstrating the model's precision.

The math reveals a cold reality: these optimized diets are almost never chosen in practice.

• Nutrition is a "credence attribute"—a shopper cannot easily verify it.
• Most people lack the computational power to balance 37 constraints while shopping.
• The model assumes 100% bioavailability of nutrients and ignores critical real-world factors:
  • The "time poverty" required to prepare raw ingredients.
  • Palatability and cultural norms.
  • Market volatility (e.g., when milk prices double, the "optimal" diet abruptly shifts).