What we only to do is to maneuver a balance between the food

原意是不是“我们只能做的是……”?如果是的话,那句子的主语应该是What we can only do ,或者照一楼的理解那样翻也是可以的,没有语法错误,最后再把food前的the去掉,修改后：
What we can only do/What we only need to do is to maneuver a balance between food and the progress of science.