This fact is explained by Vandana Shiva

范达娜·席瓦对这个事实作出说明
who is trained as a physicist

她是名印度物理学家
and works for Farmer's Rights in her native India.

在自己国家为农民权益奔走
And this is the quote:

她说道
"The analyses we have done show that no matter what,

"我们的分析表明无论如何
whether the system is highly technological or much more simple,

无论是高科技食品系统还是传统食品系统
about 50% to 60% of a population

人口总数的一半或是以上
has to be involved in the work of feeding that population."

必须参与到粮食生产的工作中"
Continue Quote:

她又说道
"Most of us who have moved off of farms

"许多不再耕种的农民进城后
are still working in the industry of creating food

仍在食品行业从事例如出纳员
and bringing it to consumers as cashiers,

货车司机甚至是石油钻塔工