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Keeping slim is good for the planet, say scientists

April 20, 2009
Courtesy London School of Hygiene & Tropical Medicine
and World Science staff

Main­tain­ing a healthy body weight is good news for the en­vi­ron­ment, ac­cord­ing to a study that ap­pears April 19 in the In­terna­t­ional Jour­nal of Ep­i­de­mi­ology.

Be­cause food pro­duc­tion is a ma­jor con­trib­u­tor to glob­al warm­ing, a lean popula­t­ion, such as that seen in Vi­et­nam, will con­sume al­most 20 per­cent less food and pro­duce few­er green­house gas­es than a popula­t­ion in which 40 per­cent of peo­ple are obese, close to that seen in the USA to­day, ac­cord­ing to au­thors Phil Ed­wards and Ian Roberts of the Lon­don School of Hy­giene and Trop­i­cal Med­i­cine.

Transport-related emis­sions will al­so be low­er be­cause it takes less en­er­gy to trans­port slim peo­ple. The re­search­ers es­ti­mate that a lean popula­t­ion of 1 bil­lion peo­ple would emit 1,000 mil­lion tons less car­bon di­ox­ide equiv­a­lents per year com­pared with a fat one.

In nearly eve­ry coun­try in the world, av­er­age body mass in­dex—a meas­ure of obes­ity—is ris­ing. Be­tween 1994 and 2004 the av­er­age male body mass in­dex in Eng­land in­creased from 26 to 27.3, the re­search­ers said. The av­er­age female body mass in­dex rose from 25.8 to 26.9, about 3 kg, or al­most 7 pounds, heav­i­er. Hu­man­kind is get­ting steadily fat­ter.

“When it comes to food con­sump­tion, mov­ing about in a heavy body is like driv­ing around in a gas guz­zler,” the au­thors said in a state­ment. “The heav­i­er our bod­ies be­come the harder and more un­pleas­ant it is to move about in them and the more de­pend­ent we be­come on our cars. Stay­ing slim is good for health and for the en­vi­ron­ment. We need to be do­ing a lot more to re­verse the glob­al trend to­wards fat­ness, and rec­og­nise it as a key fac­tor in the bat­tle to re­duce emis­sions and slow cli­mate change.”

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Maintaining a healthy body weight is good news for the environment, according to a study that appears April 19 in the International Journal of Epidemiology. Because food production is a major contributor to global warming, a lean population, such as that seen in Vietnam, will consume almost 20% less food and produce fewer greenhouse gases than a population in which 40% of people are obese, close to that seen in the USA today, according to authors Phil Edwards and Ian Roberts of the London School of Hygiene and Tropical Medicine. Transport-related emissions will also be lower because it takes less energy to transport slim people. The researchers estimate that a lean population of 1 billion people would emit 1,000 million tons less carbon dioxide equivalents per year compared with a fat one. In nearly every country in the world, average body mass index—a measure of obesity—is rising. Between 1994 and 2004 the average male body mass index in England increased from 26 to 27.3, the researchers said. The average female body mass index rose from 25.8 to 26.9, about 3 kg, or almost 7 pounds, heavier. Humankind is getting steadily fatter. “When it comes to food consumption, moving about in a heavy body is like driving around in a gas guzzler,” the authors said in a statement. “The heavier our bodies become the harder and more unpleasant it is to move about in them and the more dependent we become on our cars. Staying slim is good for health and for the environment. We need to be doing a lot more to reverse the global trend towards fatness, and recognise it as a key factor in the battle to reduce emissions and slow climate change.”