Energy cost of a strawberry

I've been hunting for this particular statistic-- ie: the caloric cost of transport versus the caloric value of the food transported (and then consumed). The standard unit is of one strawberry (in US research) and an iceberg lettuce in UK research. For example:
  1. If you are concerned about oil prices and global warming, consider this: It takes 400 calories of fossil fuels to transport a single 5-calorie strawberry from California to US East Coast supermarkets. [Reported by the Organic Consumers Association]
  2. "It takes 35 calories of fuel to bring a 5-calorie strawberry from California to New York."
  3. Energy cost of transporting strawberries from farm to market based on fuel efficiency, energy value of fuel, and cargo capacity of vehicle. Fuel efficiencies of “trucks” and “vans/pickups” are 1999 estimates from the U.S. Department of Energy, Energy Information Administration (2002). Energy values (in kcal) for diesel and gasoline are from Cervinka (1980, p 15). Cargo capacity is assumed to be 40,000lbs of produce for trucks and 1,000lbs of produce for vans/pickups.(Source p74)
  4. Thirteen kilocalories of energy is used to produce each kilocalorie of food we eat (p. 20 -- excellent statistical summary of energy consumptions --U.S. ENERGY CONSERVATION AND EFFICIENCY:BENEFITS AND COSTS -2002 ).
    Each person in the U.S. consumes about 920 kg (2,023 lbs) of food annually, or about 3,800 kcal per person per day (USDA, 2001). Supplying this food requires the expenditure of about 15.8 quads of energy per year (USBC, 2001). Put another way, about 13 kcal of fossil energy is expended per kcal of food supplied to each American.
    • Quad is a unit of energy equal to 1015 BTU, or 1.06 × 1018 Joule in SI units.[1]

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