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 prence of fast food has given people less healthy, more energy-dense options。
BMI因为食物更加容易获得和机械化运输的实现而持续上升。因为人们比30年前更加懒散，快餐的流行也给了人们健康程度降低但热量增加的选择。
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。
研究者们使用统计模型，比较了上世纪70年代英国的BMI分布数据与2010年的分布预测。前者的人口肥胖率为3.5%，而后者为40%。
"In terms of environmental impact, the lean population has a much smaller carbon footprint," Edwards said。
爱德华称：“就对环境的影响而言，体型瘦小人群的碳足迹要小得多。”
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。
研究显示，拥有40%肥胖率的人口，其所需能源消耗要比肥胖率为3.5%的人口多19%。
This 19 percent increase in food consumption translates into an increase of 270 million metric tons of greenhouse gas emissions, the study said。
这19%的食物消费增长相当于新增2.7亿吨温室气体的排放。
"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。