Researchers at the London School of Hygiene and Tropical Medicine published a study showing that, because of food production and transportation factors, a population of heavier people contributes more harmful gases to the planet than a population of thin people.

Given that it takes more energy to move heavier people, transportation of heavier people requires more fuel, which creates more greenhouse gas emissions, the authors write.

"The main message is staying thin. It's good for you, and it's good for the planet," said Phil Edwards, senior lecturer at the London School of Hygiene and Tropical Medicine.

The study offers this novel approach to the global warming problem as U.S. lawmakers discuss the future of climate change legislation. This week, the the House Energy and Commerce Committee is scheduled to begin on a comprehensive energy and climate bill. On Friday, the Environmental Protection Agency announced that six greenhouse gases pose potential health hazards, an announcement that could prompt the regulation of the gases.

More than 1 billion adults worldwide are overweight, and about 300 million are obese, the study said. Generally, the body mass index, a measure of obesity, is increasing in most countries worldwide, from China to European countries to the United States.

BMI is going up because of the availability of food and motorized transportation, Edwards said. People are less active now than they were 30 years ago, and the prevalence of fast food has given people less healthy, more energy-dense options.

Using statistical models, the authors compared the distribution of BMI in the United Kingdom in the 1970s -- when 3.5 percent of the population was obese -- with a prediction for the country's BMI distribution in 2010, reflecting 40 percent obesity.

"In terms of environmental impact, the lean population has a much smaller carbon footprint," Edwards said.

The population with 40 percent obese people requires 19 percent more food energy for its total energy expenditure than the population with 3.5 percent obese people, the study showed.

This 19 percent increase in food consumption translates into an increase of 270 million metric tons of greenhouse gas emissions, the study said.

"The findings make sense and highlight an important global co-benefit of losing weight, along with the significant personal health benefits," said Patrick Kinney, associate professor at Columbia University's Mailman School of Public Health, who was not involved in the study.

In terms of obesity rate, the U.S. population is not far off from the overweight population model in this study. The country has 33.3 percent obese people, according to the Mayo Clinic.

The study suggests that governments have a responsibility to encourage people to be more physically active, Edwards said. Active transportation, such as cycling and walking, helps maintain a healthy weight but requires safe streets, he said.

"If the government wants to promote active transport, which would be good for the environment and for individual health, it needs to make the environment safe to do that," he said.

Although climate change has come into the forefront as a major world problem recently, this is not the first time scholars have thought about the connection between fossil fuel and body fat.

In 1978, a year the United States experienced an oil shock, a study in the American Journal of Public Health showed that if all overweight people in the country aged 18 to 79 reached their optimal weight, the resulting energy savings would equal 1.3 billion gallons of gasoline.

After the dieting period, about 750 million gallons of gasoline would be saved every year, said the authors, Bruce Hannon, professor at the University of Illinois, Urbana-Champaign, and Timothy Lohman, now professor emeritus at the University of Arizona.

Today, research has shown that the obesity epidemic costs the United States about $100 billion a year, said Dr. Martin Donohoe of Portland State University, who runs the Web site Public Health and Social Justice. In terms of energy expenditure, the average food product travels 1,500 miles to get to your table, he said.

Some measures to curb obesity include making healthier meals available in schools, putting nutritional information on food packages and menus, and banning trans fats, he said.

倫敦衛生和熱帶醫學學院的研究者們發布的最新研究結果顯示，由于食品生產加工和運輸等因素，超重的人群比瘦人們向地球“貢獻”更多的有害氣體。

研究者們寫道，考慮到移動胖人需要消耗更多的能量，體重更大者的運輸就需要更多的燃料，這造成了更多的溫室氣體排放。

倫敦衛生和熱帶醫學學院的高級講師菲爾愛德華茲說，“報告主題就是要保持苗條身材。這有利于你個人，也有利于地球。”

美國立法者們正在討論有關氣候變暖立法的未來，而此時這項研究提供了一個解決全球變暖問題的新方法。眾議院能源和商務委員會定于本周提交一份綜合能源和氣候議案。周五時，環保署宣布6種溫室氣體會造成潛在的健康危害，這將推動有關氣體方面的管理。

研究稱，全球有超過十億成年人超重，其中大約有3億人過度肥胖。總體而言，從中國到歐洲，再到美國，世界大多數國家的BMI（體重指數——肥胖測量標準）一直在增長。

BMI因為食物更加容易獲得和機械化運輸的實現而持續上升。因為人們比30年前更加懶散，快餐的流行也給了人們健康程度降低但熱量增加的選擇。

研究者們使用統計模型，比較了上世紀70年代英國的BMI分布數據與2010年的分布預測。前者的人口肥胖率為3.5%,而后者為40%。

愛德華稱：“就對環境的影響而言，體型瘦小人群的碳足跡要小得多。”

研究顯示，擁有40%肥胖率的人口，其所需能源消耗要比肥胖率為3.5%的人口多19%。

這19%的食物消費增長相當于新增2.7億噸溫室氣體的排放。

哥倫比亞大學郵差公共衛生學院的副教授Patrick Kinney并未參與此項研究，但他認為：“這些結果非常有意義，它們揭示了減肥是為了全球的共同利益，對個人健康也益處良多。”

按照美國目前的人口肥胖率，研究中的超重人口模型并非遙不可及。根據Mayo Clinic的數據，美國現在擁有33.3%的肥胖人口。

愛德華認為，該項研究建議政府應承擔其責任，鼓勵人們參加更多的體育活動。諸如騎車和散步等積極的運動，可以幫助保持健康的體重，但這需要安全的街道。

“如果政府想推廣此類運動——這對環境和個人健康都有益，那么它必須創造一個安全的環境。”

雖然氣候變化最近已經作為一個世界性難題提上議程，但這并非學者們第一次考慮化石能源和人體脂肪之間的聯系。

早在1978年，美國經歷石油危機之時，《美國公共健康雜志》的一項研究就顯示，如果美國從18歲到79歲的所有超重人口都保持理想體重，那么由此節省下來的能源相當于13億加侖汽油。

據伊利諾斯大學香檳分校教授Bruce Hannon和亞利桑那大學的榮譽教授Timothy Lohman估計，在節食期過后，大約每年將節省7.5億加侖汽油。

來自波特蘭州立大學的Martin Donohoe教授說，目前研究已經顯示美國每年因肥胖癥流行損失一千億美元，按照其能源消耗計算，食品在抵達餐桌之前平均需要旅行1500英里。

他說，阻止肥胖的措施包括在學校盡量提供更健康的飲食，在食品包裝和菜單上印制營養信息，還有取締反式脂肪酸。