The Mediterranean diet became a health fad when epidemiologists looked at a region in Europe and determined that their lower heart disease was due to more fish.

A new paper uses a debunked claim "it takes a gallon of gas to make a pound of beef" and uses that to declare that a new diet would reduce global warming. The authors from the University Hospital Complex of Huelva, Jaume I University of Castellón and the University of Huelva compared the daily menus in Spain, based on a roughly Mediterranean diet, to those eaten in English-speaking countries, such as the United Kingdom and the US.



Their analysis of 448 lunches and 448 dinners throughout the four seasons, consisting of 2,000 kilocalories, included Andalusian gazpacho soup, vegetable pisto manchego, paella or the stew-like puchero. They compiled a database of the foods grown, fished or produced and the carbon footprint for each dish and menu was calculated simply by multiplying the raw amount required for its preparation. The average daily carbon footprint obtained was 5.08 kg of CO2 equivalent (CO2e), much less than the average for the US (estimated at between 8.5 kg and 8.8 kg of CO2e) or the United Kingdom (estimated at 7.4 kg of CO2e); all for the same calorific intake. The carbon footprint was also obtained for 17 other therapeutic diets such as soft, liquid or low/high-protein diets.

"The differences between the average value of the Mediterranean diet and that of English-speaking countries is due to much less beef being eaten in Spain (a food item with a larger carbon footprint) and more vegetables and fruit being eaten, which have a lower carbon footprints," says Rosario Vidal, lead author of the study and researcher in the Mechanical Engineering and Construction department at the Valencian institution. "Therefore, it is not only healthier, but our diet is also more ecological".

The problem is their definition of carbon footprint is too simplistic. A carbon footprint is a carbon dioxide equivalent causing global warming. So for methane, the the Intergovernmental Panel on Climate Change (IPCC)) claims that methane has a global warming potential of 25, which means that it is recognized as 25 kg of carbon dioxide equivalent. Except methane disappears rapidly while CO2 does not. Calling animal emissions of methane equal to 25X the CO2 is ridiculous - and the CO2 it is equivalent to, the gallon of gas to create a pound of beef, was invented by an environmental marketing group in a press release in the 1980s.

The Mediterranean diet may be healthier - but it could also be the rampant alcoholism and unemployment in Spain, if all it takes to create causation is two matching curves.

Citation: Rosario Vidal, Enrique Moliner, Andrej Pikula, Ángel Mena-Nieto y Agustín Ortega. 'Comparison of the carbon footprint of different patient diets in a Spanish hospital'. Journal of Health Services Research&Policy 2015, Vol. 20(1) 39-44.